U.S Fish & Wildlife Service
A Preliminary Biological
Assessment of Long Lake
National Wildlife Refuge
Complex, North Dakota
Biological Technical Publication
BTP-R6006-2006
U.S Fish & Wildlife Service
A Preliminary Biological
Assessment of Long Lake
National Wildlife Refuge
Complex, North Dakota
Biological Technical Publication
BTP-R6006-2006
Murray K. Laubhan1
Robert A. Gleason1
Gregory A. Knutsen2
Rachel A. Laubhan3
N. H. Euliss, Jr.1
1 U.S. Geological Survey, Northern Prairie Wildlife Research Center
8711 37th Street SE, Jamestown, ND
2 U.S. Fish and Wildlife Service, Region 6, Long Lake National Wildlife Refuge
Complex, 12000 353rd Street SE, Moffit, ND
3 U.S. Fish and Wildlife Service, Region 6, Denver, CO
Cover image credit: Title: Canvasback Hen
Alternative Title: Aythya valisineria
Creator: Dewhurst, Donna
ii A Preliminary Biological Assessment of Long Lake National Wildlife Refuge Complex, North Dakota
Author Contact information:
Murray K. Laubhan, U.S. Geological Survey, Northern Prairie Wildlife Research Center, 8711 37th St. SE,
Jamestown, ND 58401. Phone: (701) 253-5534, Fax: (701) 253-5553, e-mail: Murray_Laubhan@usgs.gov.
Robert A. Gleason, U.S. Geological Survey, Northern Prairie Wildlife Research Center, 8711 37th St. SE,
Jamestown, ND 58401. Phone: (701) 253-5546, Fax: (701) 253-5553, e-mail: Robert_Gleason@usgs.gov.
Gregory A. Knutsen, U.S. Fish and Wildlife Service, Region 6, Long Lake National Wildlife Refuge Complex,
12000 353rd Street SE, Moffit, ND, USA 58560. Phone: (701) 387-4397, e-mail: Gregg_Knutsen@fws.gov.
Rachel A. Laubhan, U.S. Fish and Wildlife Service, Region 6, Northern Prairie Wildlife Research Center, 8711
37th St. SE, Jamestown, ND 58401. Phone: (701) 253-5543, Fax: (701) 253-5553, e-mail: Rachel_Laubhan@
fws.gov.
N. H. Euliss, Jr., U.S. Geological Survey, Northern Prairie Wildlife Research Center, 8711 37th St. SE,
Jamestown, ND 58401. Phone: (701) 253-5564, Fax: (701) 253-5553, e-mail: Ned_Euliss@usgs.gov.
Recommended citation:
Laubhan, M. K, R. A. Gleason, G. A. Knutsen, R. A Laubhan, and Ned H. Euliss, Jr. 2006. A preliminary
biological assessment of Long Lake National Wildlife Refuge Complex, North Dakota. U.S. Department of
Interior, Fish and Wildlife Service, Biological Technical Publication, BTP R6006-2006, Washington, D.C.
For additional copies or information, contact:
Associate Editor: Wayne J. King
Regional Refuge Biologist
USFWS, Region 6
P.O. Box 25486
Denver Federal Center
Denver, Colorado 80225-0486
iii
Table of Contents
Acknowledgements.............................................................................................................................................. vi
Summary...................................................................................................................................................................................1
Introduction..............................................................................................................................................................................2
Description...............................................................................................................................................................................3
Refuge Establishments and Authorities..............................................................................................................................3
Long Lake NWR.................................................................................................................................................... 3
Slade NWR.............................................................................................................................................................. 3
Florence Lake NWR.............................................................................................................................................. 3
Location and Formation..........................................................................................................................................................3
Landform and Topography......................................................................................................................................................4
Soils...........................................................................................................................................................................................5
Climate......................................................................................................................................................................................6
Ground Water and Surface Water........................................................................................................................................6
Vegetation.................................................................................................................................................................................7
Wildlife Conservation...........................................................................................................................................................10
Long Lake NWR Complex.................................................................................................................................. 11
Bird Conservation Region................................................................................................................................... 12
Birds of Conservation Concern.......................................................................................................................... 13
North American Waterfowl Management Plan................................................................................................. 13
Partners In Flight North American Landbird Conservation Plan................................................................. 13
Shorebird Conservation Plan.............................................................................................................................. 14
Waterbird Conservation Region......................................................................................................................... 14
Prairie Pothole Joint Venture.............................................................................................................................. 14
Biological Assessment.........................................................................................................................................................15
Approach.................................................................................................................................................................................15
Current Conditions.................................................................................................................................................................16
Hydrology............................................................................................................................................................ 16
Sediment and Nutrient Dynamics..................................................................................................................... 17
Vegetation and Wildlife...................................................................................................................................... 20
Potential Information Needs............................................................................................................................. 21
Literature Cited......................................................................................................................................................................22
Appendix A. Scientific and common names of animals and plants mentioned in the text......................................42
Appendix B. Conservation status for avian species based on regional and national plans...................................51
Appendix C. ............................................................................................................................................................................55
Quantitative measurements of habitat structure reported in the literature that may be related to use by
select avian species: (a) vegetation height at nest sites or within breeding territories of
wetland nesting species, (b) water depth at nest sites or within breeding territories of wetland nesting
species, (c) water depth at foraging sites, (d) visual obstruction at nest sites or within breeding
territories of upland nesting species, (e) vegetation height at nest sites or within breeding territories of
upland nesting species, and (f) litter depth at nest sites or within breeding territories of upland nesting
species.
iv A Preliminary Biological Assessment of Long Lake National Wildlife Refuge Complex, North Dakota
List of Figures
Figure 1. Location of Long Lake, Slade, and Florence Lake National Wildlife Refuges, and associated
waterfowl production areas, in Burleigh, Emmons, and Kidder counties, North Dakota.................................. 38
Figure 2. Estimated annual number of avian deaths (waterfowl and other birds) due to botulism on Long
Lake National Wildlife Refuge, 1937-2004................................................................................................................ 39
Figure 3. Relationship between specific conductance (μS per cm) and dissolved matter (mg per L)................ 40
Figure 4. Estimated potential accumulation (tons) of evaporates per 30.5 cm of water that evaporates from
Units 1, 2, and 3 on Long Lake National Wildlife Refuge....................................................................................... 41
List of Tables
Table 1. General physical properties of soil associations occurring on Long Lake, Slade, and Florence
Lake National Wildlife Refuges................................................................................................................................ 27
Table 2. Properties of common soil series underlying wetland basins on Long Lake, Slade, and
Florence Lake National Wildlife Refuges................................................................................................................. 28
Table 3. Concentrations of select constituents in water from glacial drift in the vicinity of Long Lake,
Harker Lake, and Florence Lake in Burleigh and Kidder counties, North Dakota........................................... 29
Table 4. Distribution of wetland types in Burleigh and Kidder counties, North Dakota.................................... 30
Table 5. Area (ha) of cover classes on Long Lake National Wildlife Refuge in 2003........................................... 31
Table 6. Frequency of occurrence (%) of terrestrial plant associations based on 25-m belt transects in
Unit G-6 (n = 18 transects) and virgin sod units (Units G-4A, G-4B, G-4C, G-9A, and G-9B; n = 74
transects) on Long Lake and Florence Lake (n = 50 transects) National Wildlife Refuges in 2004 and
2002, respectively........................................................................................................................................................ 32
Table 7. Waterfowl breeding population estimates and recruitment rates on Long Lake National Wildlife
Refuge Complex (including the Wetland Management District), 1987-2004........................................................ 33
Table 8. Nest success on seven management units of Long Lake National Wildlife Refuge during 2002
and six Waterfowl Production Areas in the Long Lake Wetland Management District during 2001............... 34
Table 9. Number of colonial waterbird breeding pairs, number of colonies, and distribution of breeding
pairs among wetland probability classes on Long Lake National Wildlife Refuge during 2003....................... 35
Table 10. Relative abundance, estimated breeding pairs per 100 ha, and frequency of occurrence of 15
grassland/wetland edge nesting passerines on Long Lake NWR, 2001-2004...................................................... 36
Table 11. Internal tissue concentrations of essential elements that are considered adequate for most
higher plants (Salisbury and Ross 1978)................................................................................................................... 37
vi A Preliminary Biological Assessment of Long Lake National Wildlife Refuge Complex, North Dakota
Acknowledgments
Prior to writing the report, U.S. Geological Survey
personnel (Robert Gleason, Ned Euliss Jr., and
Murray Laubhan) were invited to a meeting (5
- 7 April 2004) with Long Lake National Refuge
staff (Paul Van Ningen, Gregory Knutsen, Natoma
Buskness, and Cheryl Jacobs) and U.S. Fish
and Wildlife Service Region 6 personnel (Linda
Kelly, Wayne King, Rachel Laubhan, and Adam
Misztal). The purpose was to become familiar with
certain National Wildlife Refuge lands, discuss
management opportunities and constraints, and
identify information that potentially could assist the
staff in developing a credible biological plan to guide
future management. These individuals contributed
significant time and insight regarding management
of the Long Lake National Wildlife Refuge Complex.
Thanks also to the following individuals for
providing reviews of an earlier draft: S. L. Jones, D.
G. Jorde, W. J. King, D. M. Mushet, J. D. Petty, A. J.
Symstad, and K. Torkelson.
Summary
This report represents an initial biological
assessment of wetland conditions on Long Lake
National Wildlife Refuge (NWR), Slade NWR,
and Florence Lake NWR that was conducted as
part of the pre-planning phase for development
of a Comprehensive Conservation Plan (CCP).
According to the 1997 National Wildlife Refuge
System Improvement Act (NWRSIA), decisions
guiding NWR management should be based on the
best available scientific information. Therefore, this
report attempts to integrate relevant information
from many different scientific disciplines (e.g.,
geology, hydrology, biology) to assist the U.S.
Fish and Wildlife Service (USFWS) in identifying
ecological constraints and opportunities imposed
by the land base being considered. The intent is
to provide information and ideas necessary for
evaluating the potential benefits and detriments of
management actions during the decision making
process that accompanies development of biological
goals and objectives.
Information in this report is based on a relatively
limited number of published articles, past notes, and
observations during a visit to Long Lake, Florence
Lake, and Slade NWRs. The authors only attempted
to locate sufficient relevant information necessary
to formulate more definitive ideas and provide
additional context. Thus, the information provided
below is incomplete and a more thorough synthesis
will be required. Further, interpretation of published
information can vary among individuals, and the
Long Lake NWR Complex (hereafter Complex)
staff is encouraged to review the documents cited
in this report. Many years of staff observation and
experience managing the Complex are invaluable to
ensuring that information used to make decisions
is applicable. Consequently, some sections contain
information that was not fully explored in the
evaluation section; however, the information was
retained because it may be useful as the Complex
staff and core CCP team examine different
management options. Finally, decisions regarding
management of the wetland community also require
integrating information from terrestrial lands that
impact wetlands (i.e. catchment). Although this may
seem simple and straightforward, this task often is
difficult because it frequently requires an iterative
approach to ensure that important issues that may
affect management of both wetlands and uplands
have not been omitted.
This report does not contain conclusions, nor does
it advocate any opinions (favorable or unfavorable)
regarding the biological program. Further, concepts
such as alternatives, goals, and objectives, are
not discussed. The core CCP team will address
these topics. Rather, it represents a summary that
hopefully will be used to focus future discussion
regarding biological data needs and approaches for
using this information to make decisions. Ultimately,
however, scientific information alone will not lead
to a definitive decision regarding future direction.
Also, biology is only one of many components that
must be considered in the evaluation. Therefore,
it is recommended that USFWS personnel
responsible for determining the future direction
of Complex management be consulted to establish
guidelines and agree on the approach that will be
used in evaluating the biological program prior to
proceeding.
A Preliminary Biological Assessment of Long Lake National Wildlife Refuge Complex, North Dakota
Introduction
The impetus for this report was passage of the 1997
NWRSIA that requires each NWR in the National
Wildlife Refuge System (NWRS) to develop a
CCP that includes goals and objectives that are
based on the best available science. To accomplish
this mandate, Region 6 of the USFWS contracted
with the Biological Resources Division of the U.S.
Geological Survey (USGS) to inspect wetland
habitats and synthesize available information
pertinent to the management of Long Lake, Slade,
and Florence Lake NWRs as part of a pre-planning
phase to guide development of a CCP. This report
represents the initial synthesis.
The brevity of the site visit did not allow for detailed
discussions between USGS and USFWS personnel,
but it did provide the opportunity to exchange
thoughts regarding the information needed to
evaluate the biological program. Thus, the ideas
contained within this report are of a general nature
and should be viewed as a collaborative effort that
involved the Complex staff. Additional work will
be required to objectively evaluate the biological
program, and this report should be viewed as an
initial effort to start this process. In addition, there
are alternative ways of approaching an evaluation
that would require different levels and types of
information. Therefore, the responsibility of the
USFWS is to review the report and other relevant
materials, discuss available options with appropriate
personnel, and determine if the identified
information needs and recommendations outlined
in this report are acceptable and represent the
preferred manner of proceeding.
General descriptive information on NWR
establishment, topography, climate, geology, soils,
vegetation, and wildlife is intended to provide a
brief background of these three NWRs with regard
to functions, processes, and values. The scientific
names of plants and animals used in the text
are provided in Appendix A. This information is
important as a baseline for understanding the impact
of past land alterations and for developing guidelines
for future management. In contrast, the section
on wildlife conservation is intended to provide
perspective regarding potential NWR contributions
to natural resources based on conservation plans
that have been developed for application at larger
geographic scales that encompass the NWR. The
section on evaluation of the wetland community
discusses in more detail the processes impacting
current wetland conditions. Included in this
discussion are terrestrial habitats within the
catchment because many biological features of
importance in wetlands (e.g., plants, invertebrates)
are impacted by processes (e.g., surface runoff,
water quality, erosion and deposition of sediment)
that originate in the uplands. The intent is to
provide thoughts regarding potential information
that will assist the USFWS in developing achievable
biological objectives during CCP development. The
recommendations are largely those of the authors
and are based on thoughts that resulted from
discussions with USFWS personnel during the
site visit. Further, the information needs identified
are known to be incomplete from a biological
perspective and largely ignore recreational and
other considerations. Thus, additional effort will
be required by USFWS personnel to identify and
integrate issues, concerns, and recommendations
through internal discussions and public scoping.
Description
Refuge Establishments and Authorities
All three NWRs considered in this report were
established under Executive Order and are
managed under authority of the National Wildlife
Refuge Administration Act and all other authorities
established by legislation pertaining to the NWRS.
Long Lake NWR (9025 ha) is managed as a separate
unit, whereas, Slade (1214 ha) and Florence Lake
(764 ha) NWRs are considered part of the Long
Lake Wetland Management District (WMD), a
three-county (Burleigh, Kidder, Emmons) area in
south-central North Dakota. In addition to Slade
and Florence Lake NWRs, the 69,580-ha WMD also
includes 80 waterfowl production areas ([WPA],
8711 ha), 1013 wetland easements (40,646 ha), six
easement NWRs (2342 ha), 43 grassland easements
(6556 ha), and one wildlife development area (WDA;
321 ha). The WDA was purchased and developed
by the Bureau of Reclamation and transferred to
the USFWS in 1991 for management as a mitigation
obligation of the Garrison Diversion Project (URL
http://longlake.fws.gov/Wmd.htm). The NWR
purposes are based on land acquisition documents
and authorities only (URL http://refugedata.fws.gov/
databases/purpose) and do not include purposes that
may be identified in other documents, including deed
restrictions, management agreements with primary
land managers, and congressional established
wilderness designations which were not part of the
acquisition documents and authorities.
Long Lake NWR. Established “... as a refuge and
breeding ground for migratory birds and other
wildlife ...” (Executive Order 8119, dated 10 May
1939), “... for use as an inviolate sanctuary, or for any
other management purpose, for migratory birds” (16
U.S.C. § 715d [Migratory Bird Conservation Act]),
and “... shall be administered by him [Secretary
of the Interior] directly or in accordance with
cooperative agreements ... and in accordance with
such rules and regulations for the conservation,
maintenance, and management of wildlife, resources
thereof, and its habitat thereon, ...” (16 U.S.C. § 664
[Fish and Wildlife Coordination Act]).
Slade NWR. Established “... for use as an inviolate
sanctuary, or for any other management purpose, for
migratory birds” (16 U.S.C. § 715d [Migratory Bird
Conservation Act]).
Florence Lake NWR. Established “... as a refuge
and breeding ground for migratory birds and other
wildlife ...” (Executive Order 8119, dated 10 May
1939), “... for use as an inviolate sanctuary, or for any
other management purpose, for migratory birds.”
(16 U.S.C. § 715d [Migratory Bird Conservation
Act]), and “... shall be administered by him
[Secretary of the Interior] directly or in accordance
with cooperative agreements ... and in accordance
with such rules and regulations for the conservation,
maintenance, and management of wildlife, resources
thereof, and its habitat thereon, ...” (16 U.S.C. § 664
[Fish and Wildlife Coordination Act]).
Location and Formation
All three NWRs are located in south-central
North Dakota: Long Lake NWR in Burleigh and
Kidder Counties, Slade NWR in Kidder County,
and Florence Lake NWR in Burleigh County
(Figure 1). This area is part of the Interior Plains
major physiographic division, the Great Plains
province, and the Glaciated Missouri Plateau section
(Fenneman 1931).
Preglacial drainage of the area included the
ancestral river systems of the Knife, Cannonball,
Heart, and Grand Rivers that trended northeast
and flowed into Hudson Bay (Kume and Hansen
1965). The ancient Cannonball River may have been
a tributary to the ancestral Red River (Lemke and
Colton 1958). At this time, the Missouri River flowed
northeast from the northwest corner of North
Dakota to Hudson Bay (Flint 1955).
During the Wisconsin Stage of the Pleistocene, ice
advanced four and at least three times in Burleigh
and Kidder counties, respectively (Rau et al. 1962,
Kume and Hansen 1965). The Napoleon ice sheet
(Burleigh County only) advanced first, followed by
the Long Lake, Burnstad, and Streeter advances
in both counties. Each ice advance was halted by
buttes and mesas that comprise the eastern border
of the Missouri Couteau in central North Dakota
and was followed by a period of stagnation and
melting (Rau et al. 1962). For example, the Napoleon
advance was followed by a period of glacial retreat
and erosion that may have lasted more than 25,000
years (Clayton 1962). This activity resulted in the
deposition of dead-ice moraine (i.e., landforms
composed of hummocky accumulations that are
primarily till deposited by glacial ice) behind the end
moraines and generated large amounts of outwash
(e.g., glaciolacustrine and glaciofluvial sediments) in
front of the terminal end point of each advance (Rau
et al. 1962). In addition, the ancestral Missouri River
was blocked and diverted to the southeast.
A Preliminary Biological Assessment of Long Lake National Wildlife Refuge Complex, North Dakota
The Long Lake advance occurred about 12,000 to
13,000 years ago and deposited end and ground
moraine in the eastern and western portions of
Burleigh and Kidder counties, respectively. At this
time, the valley currently occupied by Long Lake
NWR constituted part of the Cannonball River. The
preglacial valley was > 1.6 km wide and ranged
from 30 to 91 m in depth (Rau et al. 1962). The initial
lobes of the Long Lake advance followed bedrock
lows and a lobe of ice pushed along the valley of the
Cannonball River south of Steele and deposited a
great loop of end moraine in the vicinity of Long
Lake (Rau et al. 1962). As this glacier retreated,
ground moraine was deposited and meltwater flowed
through preexisting channels (stream flow was to
the south rather than the preglacial direction of
northeast) to newly formed glacial lakes McKenzie
and Steele (Rau et al. 1962, Kume and Hansen 1965).
As further melting occurred, dead-ice moraine was
deposited on bedrock highs adjacent to main valleys
and the valleys were filled with outwash and ponded
sediment because meltwater was confined behind
the end moraines that dammed the ancestral rivers
(Rau et al. 1962, Kume and Hansen 1965, Bluemle
2000).
About 12,000 years ago, the Burnstad glacier
advanced and overrode the Long Lake end moraine
in the northern part of Burleigh County and
southeastern Kidder County. The margin of the
Burnstad glacier stagnated and formed dead-ice
moraine. Meltwater transporting outwash from
this glacier flowed through Apple Creek, Random
Creek, and the Cannonball River channels into
Glacial Lake McKenzie and formed an outwash
plain in the northern portion of the lake. Cutting
and filling on the floodplain of the Missouri River
perhaps formed the higher terraces at this time.
Finally, the Streeter ice sheet advanced into
northern Burleigh and eastern Kidder counties and
deposited a number of end moraine loops along its
leading edge. As this glacier retreated, a large sheet
of outwash was deposited on the older drift from
Robinson to Lake George and filled major bedrock
valleys with stratified drift (Rau et al. 1962). This
outwash collapsed as ice from the Burnstad glacier
melted and collapsed. As melting of the Burnstad
ice continued, which may have occurred for more
than 2,000 years (Clayton 1962), the resulting
deposits of dead-ice moraine slowly assumed their
present topography. In addition, the amount of
meltwater was sufficient to eventually breach the
Long Lake end moraine and thereby allow transport
of sediment-laden waters to the Missouri River and
Glacial Lake McKenzie (Kume and Hansen 1965).
During the Recent Age (5000 years ago to present),
the area has been modified by stream erosion
and slope wash to establish the present drainage
pattern that consists of the Missouri River and its
tributaries. The present channel of the Missouri
River comprises segments representing preexisting
river channels and segments of superposed
drainage divide channels. The diverted Missouri
River channel captures many east flowing rivers
on the Missouri Plateau section, but the tributary
pattern is asymmetrical with well developed western
tributaries (e.g., Knife, Heart, and Cannonball
rivers) and underdeveloped eastern tributaries
(Snake, Painted Woods, Burnt, Apple, and Badger
creeks). In southern Burleigh and Kidder counties,
streams drain into the Long Lake trough, which also
contains Lake Etta and Lake Isabel, whereas Lake
George and Alkali Lake receive discharge from the
surface streams in the southeast corner of Kidder
County. However, the majority of intermittent
streams that originate in the end, dead-ice, and
recessional moraines flow into small lakes and
sloughs or disappear by infiltration into outwash.
Landform and Topography
The Glaciated Plains section is comprised of several
subdivisions; however, the number and boundaries of
subdivisions vary depending on the source consulted
(Fennemen 1931, Clayton 1962, Lemke and Colton
1958, Kume and Hansen 1965). This report adheres
to the boundaries proposed by Kume and Hansen
(1965), which places Long Lake and Slade NWRs
in the Long Lake Basin subdistrict of the Coteau
Slope district and Florence Lake NWR in the
Missouri Coteau district. The Coteau Slope district
is characterized by streams that are predominantly
intermittent or ephemeral and drainage that is
internal and partially integrated. The area is
subject to active erosion by integrated streams that
discharge to the Missouri River (Kume and Hansen
1965). Drift in this area is largely from the early
Wisconsin and thickness ranges from moderate to
nonexistent (Clayton 1962). More specifically, the
Long Lake Basin subdistrict largely is composed
of outwash and lake plain. Ground moraine flanks
outwash on the north and south sides of Long Lake.
The till (i.e., generally fine-grained, unstratified, and
unsorted material of various types that ranges in
size from clays to boulders) of this moraine is sandy
and pebbly, and exhibits a low undulating surface
that extends from the outwash plain adjacent to
Long Lake toward the end moraine at higher
elevations (Kume and Hansen 1965).
Long Lake NWR, as well as Lake Etta and Lake
Isabel, is situated in the partially buried valley of the
ancestral Cannonball River. The depth to bedrock
in the main valley of the ancestral Cannonball River
between Long Lake and Lake Etta was 91 m and the
difference in elevation between the depth to bedrock
on the old upland surface at Steele, North Dakota,
and the floor of the Cannonball south of this location
was > 145 m prior to glaciation. Thus, the preglacial
surface exhibited considerable relief and must have
resembled the bluffs that flank the Missouri River
trench (Rau et al. 1962). In contrast, elevations in
the basin following glaciation range from about 549
m at the edge to about 518 m in the center (Kume
and Hansen 1965). Thickness of the valley fills
range from 38 to 51 m in Burleigh County to 91 m
in Kidder County. Surface deposits are mostly sand,
but clay deposits also are common.
The Missouri Coteau district, which encompasses
Florence Lake NWR, is characterized by non-integrated
drainage and numerous undrained
depressions. The few streams that exist in
the district are of short length, tend to exhibit
ephemeral flows, and typically drain into nearby
lakes and kettles. Drift largely is from the Late
Wisconsin and thickness of glacial till ranges from
a feather edge to 50 m (average = 18 m). The area
is dominated by extensive dead-ice moraine and
associated stagnant ice-disintegration features,
including numerous kettles, disintegration ridges
and trenches, and kames (Kume and Hansen
1965). The dead-ice moraine occurs at elevations
ranging from 661 to 640 m) and maximum relief is
about 30 m. Another glacial landform in the district
is collapsed outwash topography (i.e., landforms
composed of hummocky accumulations of stratified,
primarily glaciofluvial drift sediment), which
contains abundant kettles and other ice-contact
features. Embedded within the collapsed outwash
topography are numerous saline and fresh lakes,
including Florence Lake (Kume and Hansen 1965).
Topography has been influenced by glacial activity
that reduced the local bedrock relief by abrading
and reducing the elevation of higher bedrock areas
and differentially filling valleys with glacial drift.
The maximum relief in Kidder County is 152 m, but
local relief varies from 3 to 15 m. Elevations on the
collapsed outwash range between 561 and 579 m.
Soils
Information in this section represents a general
summary intended to outline general soil
characteristics.
The bedrock in Burleigh County consists of 2438 m
of Paleozoic, Mesozoic, and Cenozoic sedimentary
rocks. The Surface bedrock includes the Late
Cretaceous Pierre (marine shale), Fox Hills (marine
sandstone), and Hell Creek (sandstone, mudstone,
siltstone, lignite, carbonaceous shale) Formations,
and the Tertiary Paleocene Fort Union Group
consisting of the Ludlow (continental sandstone,
lignite, and shale), Cannonball (marine sandstone,
siltstone, shale, and limestone), and Tongue River
(continental sandstone, claystone, siltstone, shale,
limestone, and lignite) Formations (Kume and
Hansen 1965). Beneath the glacial drift in Kidder
County, the uppermost bedrock includes the Pierre
and Fox Hills Formations of the Late Cretaceous
and the Cannonball and Tongue River Formations of
the Fort Union Group (Rau et al. 1962).
The glacial till that overlies most of the surface
bedrock in Kidder and Burleigh counties is similar
with respect to physical characteristics. There are
no significant differences in size, and differences
in color and pebble composition are subtle (Rau
et al. 1962, Kume and Hansen 1965). Grain size
analyses of 47 samples from Kidder County
indicate the sand, silt, and clay percentages of till
range from about 1.0 – 58.5, 22.0 – 45.0, and 18.9
– 77.0, respectively. However, if two samples are
excluded, ranges of grain size are 24.0 – 58.5%
sand, 13.3 – 45.0% silt, and 18.9 – 46.8% clay,
respectively (Rau et al. 1962), which is similar to
the grain analyses of 34 till samples in Burleigh
County (18.0 – 50.4% sand, 23.8 – 41.6% silt, and
23.5 – 49.9% clay) (Kume and Hansen 1965). Most
of the till in Kidder County has reddish-yellow
spots caused by oxidation of iron oxide originating
from Pierre Shale, and a white mottling caused by
concentration of calcium carbonate (Rau et al. 1962).
In Burleigh County, oxidized till occurs to depths
of 6 to 9 m and exhibits a mottled appearance due
to calcium carbonate concentrations. In addition,
free pebbles are frequently encrusted with caliche
and particles of shale and lignite are common
(Kume and Hansen 1965). In contrast, glaciofluvial
sediments in both Kidder and Burleigh counties are
comprised primarily of stratified sands and gravel
that range in size from fine sand to pebbles, whereas
glaciolacustrine sediments primarily consist of silts
and clays.
The principal parent materials of soils on all three
NWRs are glacial till, glacial outwash, and sediments
of glaciolacustrine and glaciofluvial origin. The
physical and mineralogical properties of this parent
material, in combination with long-term climatic
regimes, have greatly influenced the physical and
chemical properties of soils. Taxonomically, soils
within the boundaries of the three NWRs belong to
more than 20 series (Table 1) and nine subgroups
(typic and pachic Argiborolls; typic, entic, pachic,
and udic Haploboralls; typic Ustipsamments; typic
Natraquolls; and typic Psammaquents) (Stout et
al. 1974, Seelig and Gulsvig 1988). These soil series
form 10 associations (i.e., areas with a proportional
pattern of soils that normally consist of one or
more major soils and at least one minor soil) that
comprise the terrestrial land base of these three
NWRs. Of these, the dominant associations on all
three NWRs are loams and sands derived from
glacial outwash and glacial till that typically are
deep, medium to moderately coarse in texture,
range in available water capacity from very low to
high, and are susceptible to erosion by either wind
or water (Stout et al. 1974, Seelig and Gulsvig 1988).
Soils underlying uplands on Long Lake NWR are
sands and clays, whereas most soils underlying
uplands on Slade NWR and Florence Lake NWR
are a sand-silt mix and sandy loam underlain by
gravel, respectively (URL http://longlake.fws.gov/).
With the exception of the Lehr-Wabek-Manning
(nearly level to steep) and Harriet-Minnewaukon-
Stirum (level) associations, all other soil associations
occur in areas topographically characterized as
nearly level to rolling or gently rolling. Within each
association, individual soil series typically can be
arranged based on slope position.
Wetland features do not occupy a large proportion
of the area considered at the scale of an association;
thus, soils underlying wetlands (e.g., depression,
basins, swales, shallow drainages) are not adequately
represented at the level of the soil association.
In addition, soil associations do not adequately
address the soils derived from glaciolacustrine
A Preliminary Biological Assessment of Long Lake National Wildlife Refuge Complex, North Dakota
and glaciofluvial sediments that underlay lakes
within the boundaries of the three NWRs (Stout
et al. 1974). Soils in these series often have unique
characteristics, including highly calcareous soils
(e.g., Arveson and Colvin series), dense alkali subsoil
(e.g., Noonan series) and the presence of claypans
(e.g., Belfield, Daglum, and Rhoades series). As a
result, soils underlying wetlands often exhibit very
different properties compared to the major soils
composing an association; thus, characteristics of
individual soil series must be evaluated (Table 2). In
general, soils in these series exhibit very slow to only
moderate permeability, moderate to high available
water capacity, moderate to high organic matter
content, and medium to high fertility.
Climate
The climate of North Dakota is continental
(Rosenberg 1987, Harrington and Harman 1995),
and is characterized by relatively short, moderately
hot summers and relatively long, cold winters
(Kantrud et al. 1989). Other general climatic
features of the state include large annual and daily
temperature fluctuations, light to moderate annual
precipitation that varies in time of occurrence,
low relative humidity, and nearly continuous air
movement (Jensen undated). This large variation
is due primarily to geographic location. The Rocky
Mountains act as a barrier to the prevailing westerly
flow of atmospheric air and modify Pacific Ocean
air masses from cool and moist to mild and dry. In
contrast, cold, dry air masses originating in northern
Polar Regions and warm, moist air masses from the
Gulf of Mexico easily overflow North Dakota because
mountain barriers are lacking. Thus, the climate of
the state is influenced by cold, dry air masses from
Polar Regions, warm, moist air masses from tropical
regions, and mild, dry air masses from the northern
Pacific (Lemke 1960). These air masses flow through
North Dakota during every season and typically
progress rapidly, which causes frequent and rapid
weather changes.
Climate information in this report was obtained
from weather station 326015 operated by the High
Plains Regional Climate Center (URL http://www.
hprcc.unl.edu/) located at Moffit, North Dakota.
Depending on the variables of interest, data for this
station are available from 1948 to 2004. The average
annual temperature is 6.1o C, but the average
annual minimum and maximum temperatures
range from -1.4o to 13.0o C. Based on long-term
monthly averages, January is the coldest month
(mean = -12.4o C), followed by February (-8.7o
C) and December (-8.7o C), whereas the warmest
months are June (18.6o C), July (21.4o C), and August
(21.0o C). Further, the annual average number of
days with maximum and minimum temperatures
of > 32.2o C and < 0o C, respectively, is 25 and 73.
However, differences between monthly average
minimum and maximum temperatures are as much
as 11 to 17o C. The growing season, defined as the
long-term average number of consecutive days that
the minimum temperature does not fall below 0o C,
ranges from 99 to 147, which correlates well with
an average frost-free period of 120 days reported
for central North Dakota (Winter et al. 1984). The
average dates of last spring and first fall frosts
in Kidder County are 24 May and 13 September,
respectively, and average frost penetration is about
1.2 m (Lemke 1960, Rau et al. 1962).
Average annual total precipitation is 40.6 cm, of
which 73% (30.2 cm) occurs primarily as rain from
May through September. In contrast, the average
annual lake evaporation ranges from 83.8 to 102.0
cm) (Shjeflo 1968, Kantrud et al. 1989). Thus, the
region exhibits a negative precipitation:evaporation
ratio and lands in Burleigh and Kidder counties are
considered semiarid (Rau et al. 1962, Kume and
Hansen 1965). The annual average number of days
with precipitation events that are > 0.03 cm and >
0.3 cm are 71 and 35, respectively. In summer, most
rainfall is associated with thunderstorms (average
= 25 to 35 days per year) (Shjeflo 1968). In most
years, at least some part of the state experiences a
severe storm that produces 5.1 to 7.6 cm of rain in
24 hrs, and occasionally 12.7 to 15.2 cm or more can
occur in one day (Jensen undated). At Moffit, the
largest single day precipitation event was 11.9 cm.
In contrast, average monthly precipitation during
winter is only 2.4 cm and occurs mostly as snow.
Despite the northerly location, average annual
statewide snowfall is only 63.5 - 114.3 cm, which is
less than other northern states.
Ground Water and Surface Water
Essentially all water in this region is derived
from precipitation; however, some portion of this
water enters the ground through direct or indirect
percolation or is transported along the ground
surface to topographically lower areas. For example,
many river and stream valleys function to collect
excess surface water that cannot be absorbed into
soils at local scales. In general, ground water is
abundant in both Burleigh and Kidder counties (Rau
et al. 1962, Kume and Hansen 1965). However, the
amount of ground-water recharge that occurs varies
locally and depends on numerous factors, including
topography, climatic variables (e.g., precipitation
and temperature patterns), and soil characteristics
(e.g., available water capacity). In general, ground-water
recharge tends to be greatest during periods
of major precipitation that result in large amounts
of surface runoff (Randich and Hatchett 1966).
Further, areas dominated by alluvium (e.g., many
wetland features) and glaciofluvial silts, sands, and
gravels (e.g., valleys or channels that historically
transported glacial melt-water runoff) are
permeable and capable of collecting, transmitting,
and storing water (alluvium = 189 liters per minute
[lpm], glaciofluvial sediment yields = 568 – 3785
lpm). In contrast, lacustrine deposits comprised
of sandy silts and clays can collect and store large
quantities of water, but are generally of limited
permeability and yield only small quantities of
water (Randich and Hatchett 1966). Therefore, the
largest aquifers are located in the sands and gravels
in the Missouri River terraces and buried drainage
channels, but smaller aquifers also exist in the
sandstones and sands of the Fox Hills, Hell Creek,
Cannonball, and Tongue River Formations (Randich
and Hatchett 1966).
The chemical quality of ground water varies among
aquifers and locally depending on numerous factors,
including the materials water contacts in the
atmosphere and soil, extent of bacterial activity, soil
properties (e.g., base exchange), and the physical
interaction of surface water with ground-water
flow systems (Randich and Hatchett 1966, Lissey
1971, Winter 1977, Swanson et al. 1988). Although
limited, available water quality data obtained from
wells (domestic and stock) within or near each of the
NWRs suggest differences occur within and among
sites with different geologic material (Table 3). For
example, the specific conductance of ground water
on Long Lake NWR ranged from 734 mmhos per
cm in glacial drift to 2496 mmhos per cm in Foxhills
sandstone, whereas concentrations of sulfate ranged
from 2.7 ppm in Foxhills sandstone to 131.0 ppm in
glacial outwash. Differences also exist within the
same material on Long Lake NWR. For example,
concentrations of sodium and bicarbonate in ground
water collected from glacial drift material ranged
from 33 to 246 ppm and 329 to 641 ppm, respectively
(Randich et al. 1962, Randich and Hatchett 1966,
Table 3).
In general, the chemistry of precipitation is
relatively free of contaminants. However, as excess
rainwater (i.e., above soil saturation) is transported
across the soil surface (i.e., runoff) it can accumulate
various materials (e.g., agrichemicals) prior to
discharging into a wetland basin. The concentration
of these constituents is further modified by
climate. For example, all three NWRs are located
in a climatic zone characterized by a negative
precipitation:evaporation ratio that concentrates
chemical constituents seasonally and intra-annually
due to evapotranspiration. Thus, the surface water
chemistry of wetlands tends to be dynamic because
of complex interactions among numerous factors,
including the position of the wetland in relation to
ground-water flow systems, chemical composition
of ground water, surrounding land uses, and
climate (LaBaugh et al. 1987, Swanson et al. 1988,
Winter 2003). Given the variability within and
among wetland basins, it is not possible to provide
a general characterization of surface water quality
for these three NWRs. However, water quality of all
three units of Long Lake NWR has been recorded
previously. In May of 1969, several water quality
parameters were collected at the following locations:
(1) on the east and west sides of a road crossing
Long Lake, (2) Upper Harker and Harker lakes on
Slade NWR, and (3) Lake Isabel that adjoins Slade
NWR on the west (Swanson et al. 1988). The pH of
water at both Long Lake locations was about 9.0,
total alkalinity (mg per L) was 480 (west) and 860
(east), specific conductance (μS per cm) was 1560
(west) and 4150 (east), and sulfate concentration (mg
per L) was 900 (west) and 1185 (east). In contrast,
the pH of water in lakes on Slade NWR ranged from
8.7 (Upper Harker) to 9.3 (Harker), total alkalinity
(mg per L) ranged from 950 (Upper Harker) to 1540
(Harker), specific conductance (μS per cm) ranged
from 2300 (Isabel) to 4700 (Harker), and sulfate
concentrations (mg per L) ranged from 350 (Isabel)
to 1050 (Harker). Although quantitative reports of
water quality were not located for Florence Lake
NWR, the values obtained illustrate the differences
that can occur among lakes within similar
physiographic areas (e.g., subdistricts, districts).
In addition, differences can occur within different
portions of the same basin. For example, in April
2004 the specific conductance (μS per cm) of water
in Long Lake NWR Unit 1, Unit 2, and Unit 3 was
1910, 2600, and 4200, respectively (RAG).
In March of 1989, another water quality study was
conducted on Long Lake NWR (Olson and Welsh
1991). Complete data from this report were not
located, but concentrations of certain elements
were provided. In general, the alkalinity and
nutrient concentrations of Long Lake surface
water were high, which is typical of prairie lakes in
this region; however, elevated mercury and boron
concentrations and high sodium concentrations
also were documented (Swanson et al. 1988). Given
the alkalinity of the lake, however, the observed
mercury concentrations in surface waters would not
be readily activated biologically.
Vegetation
Historically, the landscape of south-central North
Dakota was characterized by numerous wetlands
embedded in a background matrix of northern
mixed-grass prairie (Fennemen 1931). Distribution
and density of wetlands was correlated with various
glacial landforms in the region. The greatest area
of semipermanent palustrine wetlands occurred
in areas of dead-ice and terminal moraine (e.g.,
Missouri Coteau), whereas the greatest area of
temporary and seasonal wetlands occurred in the
ground moraine and lake plain (Kantrud et al. 1989).
In contrast, rivers and lakes occurred predominantly
in topographically low areas that transported
meltwater from retreating glaciers.
The composition of vegetation in wetlands changes
dynamically in response to numerous factors,
including short- and long-term hydroperiods and
water chemistry (Kantrud et al. 1989, Euliss et al.
2004). Most palustrine basins exhibit concentric
zones of vegetation that are dominated by different
plant species (Kantrud et al. 1989). The most
commonly used terms to refer to these zones are,
in decreasing order of water permanency, deep
marsh, shallow marsh, and wet meadow (Kantrud
et al. 1989). The water regime in a deep marsh zone
usually is semipermanent. Dominant plants include
cattail, bulrush, submersed or floating plants,
and submersed vascular plants, but this zone also
may be devoid of vegetation if bottom sediments
are unconsolidated. Shallow marsh zones usually
are dominated by emergent grasses, sedges, and
some forbs, but submersed or floating vascular
plants also may occur. Wet meadow zones also
are typically dominated by grasses, rushes, and
A Preliminary Biological Assessment of Long Lake National Wildlife Refuge Complex, North Dakota
sedges, but submersed or floating plants are absent.
The primary difference between these zones is
hydroperiod. Surface flooding of the shallow marsh
zone usually is seasonal and ranges from spring to
mid- or late summer. In contrast, inundation of the
wet meadow zone typically is only temporary (e.g.,
one to several weeks in spring or briefly after heavy
summer rains).
The gradient from fresh to hypersaline water
is a continuum, and any divisions are arbitrary
(Euliss et al. 2004). In addition, salinity levels can
fluctuate widely within and among seasons (Stewart
and Kantrud 1972). In general, however, surface
water in temporary and seasonal wetland basins is
usually fresh (< 500 micromhos per cm) or slightly
brackish (500 - 2000 micromhos per cm), whereas
semipermanently flooded basins are often brackish
(5000 – 15,000 micromhos per cm), but can range
from fresh to subsaline (1500 0- 45,000 micromhos
per cm) (Stewart and Kantrud 1971). Although the
general effect of increased salinity in any zone of
wetland vegetation is a decrease in species diversity,
it is difficult to establish meaningful salinity
tolerances for individual species in their natural
habitats because of the complex interaction of abiotic
factors. However, general estimates of salinity
tolerance are available for numerous emergent and
aquatic plant species (Kantrud et al. 1989).
Uplands historically were comprised of warm-season
grasses characteristic of both the short-grass
prairie and the cool- and warm-season grasses
characteristic of the tall-grass prairie (Samson
et al. 1998); thus, the area represented a zone of
ecotonal mixing that included a diversity of short,
intermediate, and tall grass species (Bragg and
Steuter 1996). Vegetation composition at regional
and local scales was determined by numerous
interrelated factors, including elevation, topography,
climate, soil characteristics, herbivory, and fire
(Hanson and Whitman 1938, Coupland 1950, URL
http://www.worldwildlife.org/wildworld/profiles/
terrestrial/na/na0810_full.html). The mixed-grass
prairie in North Dakota has been classified into nine
major vegetation types based primarily on plant
species composition and topography (Hanson and
Whitman 1938). Species typical of all these types
include western wheatgrass, blue grama, prairie
junegrass, needle-and-thread, Sandberg’s bluegrass,
little bluestem, needleleaf sedge, and threadleaf
sedge (Whitman 1941, Kantrud and Kologiski 1982).
However, even within a vegetation type, local
variation exists. For example, in xeric areas the
blue grama, needle-and-thread, and threadleaf
sedge association also included western wheatgrass,
prairie junegrass, and needleleaf sedge as less
important dominant grasses and about 12 dominant
forbs (e.g., lotus milkvetch, narrowleaf goosefoot,
scarlet beeblossom, flatspine stickseed, stiffstem
flax, spiny phlox, woolly plantain) (Hanson and
Whitman 1938, Coupland 1992). In contrast, more
mesic areas in the same association supported more
slender wheatgrass, fendler threeawn, sideoats
grama, little bluestem, porcupine grass, green
needlegrass, and sun sedge, whereas dominant
forbs included tarragon, prairie sagewort, white
sagebrush, blacksamson echinacea, and white
milkwort (Sarvis 1920). Other associations include
those on sandy loams and fine sandy loams that
typically occurred on topographically high areas, as
well as those that tended to occur in depressional
areas dominated by silt loams and silty clay loams
characterized by increased soil moisture and high
concentrations of carbonates and soluble salts. The
former were dominated by grasses in the Bouteloua
(grama) and Stipa (needle-and-thread, green needle,
porcupine) genera, and sedges in the Carex genus,
whereas the latter were characterized by species
such as inland saltgrass, Nuttall’s alkaligrass, and
foxtail barley (Hanson and Whitman 1938).
Human alteration (e.g., conversion to agricultural
production) of the landscape has resulted in the loss
of > 50% of wetlands (Dahl 1990) and 68% of mixed-grass
prairie in North Dakota (Samson et al. 1998).
The current total wetland area is 38,342 and 52,831
ha, respectively, in Burleigh and Kidder counties
(Reynolds et al. 1997, Table 4). Semipermanent
wetlands (11,952 ha) and lakes (24,313 ha) constitute
the greatest wetland area in Burleigh and Kidder
counties, respectively; however, seasonal wetlands
occur in the highest density in both counties
(Burleigh County = 6.16 per km2, Kidder County
= 6.66 per km2) (Reynolds et al. 1997). Further,
approximately 68% of the land in the counties
(Burleigh, Kidder, and Emmons) that comprise
all three NWRs and the WMD remains in native
grassland (URL http://mountain-prairie.fws.gov/
reference/briefing_book_nd_2000.pdf). However,
in addition to habitat loss and fragmentation, the
ecological processes determining the structure and
function of remaining native communities also have
been severely impacted. For example, the World
Wildlife Organization considers the mixed-grass
prairie among the most disturbed of all grassland
ecoregions; only a few remnant patches remain
and none are considered intact (URL http://www.
worldwildlife.org/wildworld/profiles/terrestrial/
na/na0810_full.html). Major perturbations include
altered hydrology (e.g., ground water withdrawal,
construction of dams), the use of pesticides (e.g.,
in 1991 more than 100,000 metric tons applied in
the mid-continent; Samson et al. 1998), cessation
or alteration of historic burning regimes, modified
animal communities, and introduction of exotic
plants.
The above impacts are evident on portions of each
NWR considered in this report. Most lakes and
wetlands occurring on Long Lake NWR are located
in and along the distal side of morainal areas that
exhibit nonintegrated drainage. Water in these
areas is collected locally and dissipates primarily by
evapotranspiration and percolation into the water
table. However, following purchase by the USFWS
in the 1930s, the Civilian Conservation Corps (CCC)
constructed three dikes to control water levels in
Long Lake, built several small dams across ravines
that discharged water to Long Lake for the purpose
of ponding water in additional areas, and constructed
19 duck nesting islands in Units 1 and 2 of Long
Lake (URL http://longlake.fws.gov/History.HTM).
Many upland areas purchased as part of Long Lake
NWR previously had been cultivated under private
ownership. After acquisition by the USFWS, some
of these lands continued to be cultivated, some were
planted with tame grass mixes, and most continued
to be invaded by noxious exotic plants (e.g., Canada
thistle, absinth wormwood).
The current composition of wetlands on Long Lake
NWR (total = 7096 ha), based on National Wetland
Inventory (NWI) data provided by Complex staff,
includes lakes (6558 ha), semipermanent wetlands
(187 ha), seasonal wetlands (25 ha), temporary
wetlands (116 ha), and riverine habitat (6 ha, Table
5). In addition, Complex staff completed a habitat
inventory in 2003 that recorded 34 wetlands (11.2
ha) not classified by NWI. Long Lake, a 6071-ha
alkaline basin, is the predominant wetland on Long
Lake NWR. The remaining wetland area consists
of Long Lake Creek (riverine), natural wetlands,
dugouts, and man-made impoundments. Water-level
management is the primary strategy used to
manipulate wetland conditions on Long Lake and
adjacent marshes, but control often is limited. For
example, in some years water can be transported
to Unit 2 Marsh via gravity flow or pumping, but
dewatering can only occur by evapotranspiration.
The vegetation composition of wetlands on Long
Lake NWR is dynamic as evidenced by past reports
and observations of Complex staff. For example,
the presence of single-celled green algae, blue-green
algae, and phytoplankton (diatoms and
cyanobacteria) have been reported previously
(Metcalf 1931, Olson and Welsh 1991) and a plant
survey conducted in 1917 indicated that abundant
emergent plant species in Long Lake included
cosmopolitan bulrush, tule bulrush, and three-square
bulrush. This survey also reported common
spikerush as common, seaside arrowgrass, prairie
cordgrass, and common bladderwort as fairly
common, and softstem bulrush as rare (Metcalf
1931). In addition, aerial photographs of Long Lake
indicate dense stands of emergent growth, including
many species mentioned in the 1917 survey, have
been present in the units during past years (GAK).
During the site visit, algae were evident in the Long
Lake units but emergent and submergent vegetation
along the perimeter was minimal at the few locations
examined. Emergent vegetation in Unit 2 Marsh
included bulrush, cattail, common reed, prairie
cordgrass, saltgrass, seepweed, kochia, dock, and
cocklebur. However, a sufficient number of sites
were not visited to adequately characterize the
current composition or extent of wetland vegetation
and, unfortunately, the Complex staff does not have
an established monitoring program that would allow
an objective examination of vegetation dynamics in
wetlands.
Uplands (total = 1924 ha) on Long Lake NWR are
dominated (> 50% cover) by grasses (1531 ha),
noxious weeds (56 ha), shrubs (161 ha), trees (19
ha), and crops (142 ha, Table 5). Of the grassland
area, about 1416 ha consist of areas dominated
by non-native grasses, whereas introduced cool-season
grasses and legumes (i.e., dense nesting
cover [DNC]) occupies 72 ha). In contrast, the
area dominated by natives is only 11 ha and is
highly fragmented (n = 42 patches) (Table 5).
Areas dominated by noxious or invasive weeds
other than non-native grasses occur primarily
as scattered, small patches. Principal non-grass
noxious or invasive weed species are Canada thistle
(30 ha) and absinth wormwood (26 ha), with lesser
amounts of Russian olive and leafy spurge. Much
of the historic cropland on Long Lake NWR has
been seeded to native grass mixtures, tame grass,
or DNC; however, about 142 ha are still cultivated
(small grains = 133 ha, row crops = 9 ha) as part of a
seedbed preparation strategy for eventual reseeding
to native grasses. For example, approximately 73 ha
of farm fields were seeded to native grasses in 2002.
Other techniques used to manipulate the species
composition and structure of existing herbaceous
upland vegetation (native and non-native) includes a
combination of haying, grazing, prescribed burning,
and, in areas dominated by noxious or invasive plant
species, chemical and biocontrol agents.
In addition to the general vegetation characteristics
mentioned above, more detailed information on
upland plant species composition is available for six
priority management units on Long Lake NWR.
Permanent belt transects (25-m length) were
established in these units using a stratified-random
approach and methods (Grant et al. 2004). Strata
consisted of three site types (i.e., xeric, northeast
slopes, southwest slopes) and, within each unit-strata
combination, one transect was established
per 4 ha. One of these management units (G-6) was
seeded to a mix of cool and warm season native
grasses in June 2002; however, only 79% of this
74 ha unit was actually seeded. Based on 900 data
points (n = 18 belt transects) collected in 2004, the
frequency that native and exotic vegetation occurred
along transects was 36.2% and 63.8%, respectively.
These data also indicate that 6.4% and 59.7% of
G-6 currently is moderately and heavily invaded
by exotic plants, respectively (Table 6). The other
five units are comprised of virgin sod with a similar
land use history; thus, data for these units were
combined. In 2004, the frequency of native and
exotic vegetation occurrence along 74 belt transects
(n = 3700 points) in these five units was 19.8% and
80.2%, respectively. Further, these data indicate that
22.98% and 61.94% of these units are moderately and
heavily invaded by exotic plants, respectively (Table
6).
Prior to USFWS ownership, the land that now
comprises Slade NWR was purchased by Mr. Slade
in the mid-1920s for a private shooting club. During
the drought period of the 1930s, the land was tilled
to provide wildlife food, a large well (60,567 L per
10 A Preliminary Biological Assessment of Long Lake National Wildlife Refuge Complex, North Dakota
hr) was dug between Harker and Upper Harker
lakes, and a system of pipes and flumes was used
to transport water to the lakes. In addition, large
quantities of grain were purchased and shipped to
the area to provide supplemental food for waterfowl.
Currently, wetlands on Slade NWR are comprised
of five semipermanent wetlands, 15 temporary or
seasonal wetlands, and several manmade wetlands
(e.g., dugouts). Total wetland area is about 395
ha, with lakes and marshes predominating. Trees
occupy the margin of some wetlands and dead
widgeon grass was evident along the shoreline of at
least one lake. Other emergent vegetation recorded
in seasonal wetlands during the site visit included
smartweed, sedges, reed canary grass, and common
reed. Additionally, 26 aquatic and semiaquatic
plant species were identified during a 1968 survey,
including four species of bulrush, six species of rush,
narrow-leaved cattail, sprangletop, muskgrass,
American milfoil, common bladderwort, and sago
pondweed (GAK). There is evidence that the
temporary and seasonal wetlands had been farmed
prior to NWR establishment.
The balance of land (820 ha) comprising Slade NWR
is terrestrial and includes native grassland (81
ha), tame grass (522 ha), shelterbelts (16 ha), and
agricultural units (197 ha) (URL http://longlake.
fws.gov/Slade.HTM). The dominant tame grasses
are smooth brome and Kentucky bluegrass, and the
dominant noxious weed is leafy spurge. The majority
of farming on the NWR is organic. Terrestrial
lands periodically are hayed and grazed, and areas
dominated by leafy spurge are treated with a
combination of chemicals, biocontrol (e.g., beetles),
and haying.
Florence Lake NWR includes 594 ha of fee title and
170 ha of easement land (URL http://longlake.fws.
gov/FlorenceLake.HTM). Collectively, all or portions
of 78 wetland basins occupy 108 ha of this land base.
Based on NWI data, these basins are classified as
lakes (n = 4), semipermanent wetlands (n = 7),
seasonal wetlands (n = 56), and temporary wetlands
(n = 11). However, aerial photography indicates that
numerous smaller depressions were not mapped
(GAK). Based on a historic survey conducted in
1917, common spikerush and tule bulrush were
common in Florence Lake and sago pondweed and
spike watermilfoil were abundant (Metcalf 1931).
A current survey has not been conducted, but
scattered small patches of bulrush were noted along
the perimeter of some lakes, whereas spikerush,
smartweed, and pondweed were noted in a small
seasonal wetland during April 2004 (MKL).
The remainder of Florence Lake NWR consists of
native (395 ha) and tame (82 ha) grass, woodland
(6 ha), and crops (127 ha). Although approximately
82% of grasslands are often referred to as native,
baseline vegetation monitoring indicate current
species composition has been compromised to
varying extents (Table 6). Sampling methodology
was consistent with that of the belt transect data
collected on Long Lake NWR in 2004 (Grant et al.
2004). Based on 50 belt transects (n = 2500 data
points) established at varying locations on Florence
NWR, the frequency of native and exotic vegetation
occurrence along transects in 2002 was 7.0% and
93.0%, respectively. Further, these data indicate that
39.4% and 57.2% of the prairie has been moderately
and heavily invaded by exotic plants, respectively
(Table 6). Finally, farming has occurred periodically
on Florence NWR since the early 1960s, but crop
yields in recent years have been marginal. Thus,
the cooperative farming agreement on 45 ha of fee
title land was not renewed when it expired and these
areas were seeded to grass in 2000. The current 127
ha of crops occur only on easements that are not
controlled by the USFWS.
Wildlife Conservation
The primary purpose of NWR lands considered in
this report is as a breeding ground for migratory
birds and other wildlife; thus, any discussion
regarding management in relation to long-term
sustainability must be placed in this context. In
addition, the 1997 NWRSIA mandates that each
NWR develop a CCP consistent with the principles
of sound fish and wildlife management and available
science (Public Law 10557). The NWRSIA specifies
that each CCP shall identify and describe the
purposes of each NWR; the distribution, migration
patterns, and abundance of fish, wildlife, and
plant populations and related habitats; significant
problems that may adversely affect the populations
and habitats of fish, wildlife, and plants and the
actions necessary to correct or mitigate such
problems; and, to the maximum extent practicable
and consistent with the NWRSIA, be consistent
with fish and wildlife conservation plans of the state
in which each NWR is located. Although important,
the purpose of this report is not to fully develop
information on all species potentially occurring
on all three NWRs. However, some general
future direction must be specified with regard to
wildlife given the purpose for establishment of
each NWR. Therefore, this report concentrates on
the importance of all three NWRs for migratory
birds because they represent a primary USFWS
responsibility under requirements of the Migratory
Bird Treaty Act of 1918 (16 U.S.C. § 715d). However,
this focus should not be interpreted as meaning
other vertebrates, invertebrates, and plants can
be ignored because they are critical to proper
system function. In addition to various metrics of
biodiversity, lands of each NWR also contribute to
other ecosystem services at various spatial scales,
including floodwater storage, erosion control, and
water quality. Thus, information regarding other
natural resource values provided by each NWR
also should be developed and integrated prior to
evaluating the direction of future management.
Baseline information on the avian community of each
NWR considered in this report was developed using
a variety of data, including the 2002 version of the
Long Lake NWR Bird List, which is periodically
updated by Complex staff (URL http://longlake.
fws.gov/birdlist.HTM). Naming conventions for all
11
birds follows the American Ornithologists’ Union
Committee on Classification and Nomenclature
(American Ornithologists’ Union 1998, 2000, 2002,
2003). Several qualifying factors must be considered
when considering this species list. First, the 26
accidental species documented on Long Lake
NWR are not considered in this report. Second,
the list is based on bird sightings over a long
time period and it may not accurately represent
the current avian community. Third, the list only
reflects occurrence; thus, species populations on
each NWR are not known. Regardless of these
constraints, a list of avian species known to occur on
at least one of the NWRs considered in this report
can help focus discussion among individuals (e.g.,
USFWS personnel, core CCP team) responsible for
determining the future management direction.
The NWRSIA states that national and regional
plans must be consulted in developing a CCP. To
provide overall perspective, relevant information
regarding avian species of concern and population
targets contained in a representative sample of
these plans has been summarized (Appendix B),
but no attempt has been made to prioritize or make
decisions regarding species or guilds that should
receive attention. In some cases, species considered
to be of conservation concern at a regional level may
not be of concern at a national level, or vice versa.
Such differences do not indicate discrepancies;
rather, they suggest differences in distribution
and population status at different geographical
scales. Also, some species mentioned in regional
and national plans may not be incorporated in
the table even though one or more of these three
NWRs may potentially provide valuable resources
for those species. The relatively small size of each
NWR considered in this report precludes providing
quality habitat for all species and decisions likely will
be required to evaluate tradeoffs in management
approaches and for development of detailed habitat
objectives.
Long Lake NWR Complex. The importance of
NWR lands (including the WMD) for waterbirds was
a prime impetus for originally acquiring lands in fee
title and also for subsequent expansion of the land
base via fee title and easement acquisitions. Since
1987, the USFWS has conducted annual population
surveys of 13 waterfowl species in each of 15 WMDs
throughout the Dakotas and northeastern Montana.
Information derived from this survey includes
number of recruits, recruitment rates (i.e., the
number of young females fledged per adult female
in the breeding population), number of breeding
pairs, number of wet ponds, and wet area. Of the
13 primary duck species breeding in the Prairie
Pothole Region, the number of breeding pairs that
used lands comprising the Long Lake Complex
and surrounding private lands within the WMD
ranged from 8865 in 1990 to 544,017 in 1997, whereas
recruitment rates ranged from 0.40 in 1990 to 0.82
in 1997 (Table 7). According to the USFWS (1996),
a minimum recruitment rate of 0.49 is needed to
maintain a duck species’ population. Additionally,
positive relationships between wetland condition
(i.e., wet area, number of wet ponds) and both
breeding pairs and duck recruitment can be seen
throughout the 18-year survey period.
Information on nesting waterfowl is available from
upland fields on six WPAs (156 ha) in the Long
Lake WMD that were evaluated in 2001 and seven
management units (168 ha) on Long Lake NWR
evaluated in 2002 (GAK). Only fields dominated by
perennial cover and supporting > 31 duck pairs
per km2 were selected for study on WPAs, whereas
sites on Long Lake NWR were randomly selected.
Vegetation composition of fields evaluated ranged
from planted dense nesting cover, tame grass fields,
and native grassland on WPAs to exotic cool season
grass (e.g., Kentucky bluegrass, smooth brome) on
Long Lake NWR. Nest density on WPA fields was
approximately 0.76 per ha and Mayfield (Mayfield
1961) nest success (n = 110) of all species (n =
7) and study fields combined was 26.8%, which
is greater than the 15.0% nest success generally
accepted as the minimum for duck population
stability in this region (Cowardin et al. 1985, Klett
et al. 1988). However, Mayfield (Mayfield 1961)
nest success of individual fields ranged from 4.2% to
38.8% (Table 8). Nest density on Long Lake NWR
management units was approximately 1 per 2 ha and
Mayfield (Mayfield 1961) nest success (n = 79) of all
species (n = 6) and fields combined was only 3.0%
(range among individual study fields = 0.4 to 17.8%;
Table 8). The predominant nest predator on both the
WPA fields and Long Lake NWR management units
evaluated was the striped skunk; however nests also
were predated by badger, raccoon, and red fox.
Excluding accidental species, the 2002 Long Lake
NWR Bird List indicates that 278 species have been
recorded on Long Lake NWR or private land in
close proximity to the NWR, of which 129 have been
documented as nesting. This diversity of bird life
has resulted in national recognition of both Kidder
County and Long Lake NWR as two of the top 10
birding “hot spots” in the nation (Konrad 1996).
Long Lake NWR also is recognized as a Globally
Important Bird Area (IBA) (URL http://www.
abcbirds.org/iba/). The IBA program, initiated by
BirdLife International in Europe in the mid-1980s,
was developed to recognize and support sites of
importance to birds (Kushlan et al. 2002).
Long Lake NWR was designated as a regional
shorebird site in the Western Hemisphere Shorebird
Reserve Network (WHSRN) in 2002 because more
than 20,000 shorebirds use this NWR annually as
either a migratory stopover or breeding area (URL
http://www.manomet.org/WHSRN). From 2001 to
2004, shorebird surveys have been conducted on
Long Lake NWR following Manomet Center for
Conservation Sciences’ International Shorebird
Survey protocol. Although two survey routes have
been established, most surveys have been conducted
on the west route (comprised of the western 33% of
Long Lake NWR). From 2001 - 2003, 28 shorebird
species were recorded annually on Long Lake NWR,
12 A Preliminary Biological Assessment of Long Lake National Wildlife Refuge Complex, North Dakota
compared to 29 species in 2004. During this period,
the most abundant spring migrants include Wilson’s
Phalarope and Marbled Godwit, whereas the most
abundant fall migrants included Wilson’s Phalarope,
Long-billed and Short-billed dowitchers, American
Avocets, and Killdeer. Both shorebird abundance
and diversity has varied seasonally and annually
throughout the survey period; abundance has
ranged from 17,685 in spring 2004 to 1551 in spring
2003, whereas Simpson’s Diversity Index (Simpson
1949) (range = 0.0 [low] to 1.0 [high]) values have
varied from a seasonal low of 0.4978 to an annual
high of 0.8218 (GAK). The substantial variation in
shorebird abundance likely is related to wetland
conditions at scales greater than Long Lake NWR.
During years when numerous prairie wetlands are
flooded and the water level in Long Lake is high
(i.e., spring 2003), relatively few shorebirds use
Long Lake NWR. Conversely, substantially more
shorebirds use Long Lake NWR during years of
minimal spring runoff (i.e., spring 2004) because the
surrounding landscape is mostly dry and Long Lake
provides suitable shorebird habitat.
Also during 2002, wetlands within the boundaries
of Long Lake NWR and 10 WPAs (eight Bureau of
Land Management transfer tracts) were designated
as critical habitat for the federally threatened
Piping Plover by the USFWS, Division of Ecological
Services. Three fee title sites (Rath WPA, Rachel
Hoff WPA, and Long Lake NWR) designated as
Piping Plover critical habitat have been surveyed
at five-year intervals, beginning in 1991, as part of
the International Piping Plover Breeding Census
(GAK). This is a complete census intended to
provide moderate- and long-term information
necessary to assess the success of Piping Plover
recovery efforts and objectives (Ferland and Haig
2002). During the three survey years, 13 adults (six
on Rachel Hoff WPA and seven on Long Lake NWR)
were detected in 1991, five adults were detected on
Rachel Hoff WPA in 1996, and seven adults (two on
Rachel Hoff WPA and five on Long Lake NWR) and
three young (all on Rachel Hoff WPA) were detected
in 2001 (GAK).
The importance of the Long Lake NWR Complex to
colonial nesting waterbirds has been investigated.
In 2003, an aerial survey of all wetland basins (n =
864) on fee title lands within the Long Lake NWR
Complex was completed and each wetland was
assigned to one of three categories (high probability
[HPC], moderate probability [MPC], and low
probability [LPC]) based on the likelihood that the
basin would support one or more waterbird colonies
that year. Category assignments were based on
a combination of habitat conditions, including (1)
wetland cover type (Stewart and Kantrud 1971),
(2) hydrologic regime and basin size (based on NWI
data), and (3) special features (e.g., islands, dead
trees in wetland). All of the HPC wetlands (n =
68) were ground surveyed for waterbird colonies,
whereas 50% of the MPC wetlands (n = 83) and 5%
of the LPC wetlands (n = 32) were ground surveyed.
When a waterbird colony was located, species
composition was determined, nests were tallied, the
perimeter of the colony was delineated using a global
positioning system, and general habitat variables
were measured.
Forty colonies were located during the survey,
including 31 (77.5%) marsh colonies, eight (20%)
ground or island colonies, and one (2.5%) tree or
shrub colony. Twenty-four (60.0%) of the forty
colonies consisted of only one species, 11 (27.5%)
contained two species, three (7.5%) contained three
species, one (2.5%) contained five species, and one
(2.5%) contained eight species. Fourteen different
breeding waterbird species were recorded, but only
the Double-crested Cormorant utilized multiple
colony types. The number of breeding pairs of
each species detected during the survey ranged
from three pairs of Snowy Egret to 310 pairs of
California Gull (Table 9). Thirty-eight colonies
(95%) were located on HPC wetlands, whereas only
two (5%) colonies were located on MPC wetlands
and no colonies were located on LPC wetlands
(Table 9). The apparent success of the wetland
stratification scheme provided a colonial nesting
waterbird population estimate for NWR lands that
had low variance and provided an accurate estimate
of colonial nesting waterbird use of fee title lands
during the 2003 breeding season.
Finally, the Complex staff has monitored the relative
abundance and species composition of grassland/
wetland edge nesting passerines on Long Lake
NWR at 50 randomly selected 100-m radius points
annually from 2001 to 2004. Relative abundance
(mean number of breeding pairs per point),
estimated mean pairs per 100 ha, and frequency
of occurrence (percentage of total points at which
a species was detected) were calculated for all
detected species (Table 10). The number of species
detected annually ranged from 10 in 2002 to 14 in
2004 and the number of breeding pairs ranged from
258 in 2003 to 378 in 2004.
Bird Conservation Region. Lands of the Long
Lake NWR Complex are in the Prairie Pothole Bird
Conservation Region (BCR 11), an ecologically
distinct region of 715,000 km2 with similar bird
communities, habitats, and resource management
issues (North American Bird Conservation
Initiative, URL http://www.nabci-us.org/map.
html). The Prairie Pothole BCR comprises the core
breeding range of most dabbling duck and several
diving duck species, as well as provides critical
breeding and migration habitat for > 200 other
bird species. There are 29 species of conservation
concern listed for BCR 11 (USFWS 2002), all of
which have been recorded as occurring on Long
Lake NWR (Appendix B). Priority wetland species
that breed in the area include Yellow Rail, Piping
Plover, American Avocet, Marbled Godwit, Wilson’s
Phalarope, and Franklin’s Gull. In addition, wetland
areas in the region also provide important migration
habitat for the American Golden-Plover, Hudsonian
Godwit, White-rumped, and Buff-breasted
sandpipers. Priority species that breed in terrestrial
13
habitats include Sprague’s Pipit, Baird’s Sparrow,
and Chestnut-collared Longspur (USFWS 2002).
Birds of Conservation Concern. The Birds of
Conservation Concern (BCC) is the most recent
effort to satisfy the 1988 amendment to the Fish
and Wildlife Conservation Act, which mandates
the USFWS to “…identify species, subspecies, and
populations of all migratory nongame birds that,
without additional conservation actions, are likely to
become candidates for listing under the Endangered
Species Act of 1973” (USFWS 2002). The document
provides species lists at three geographic scales:
national, USFWS regions, and BCRs. Species
considered for inclusion include nongame birds,
game birds without hunting seasons, and numerous
categories (candidate, proposed endangered or
threatened, and recently delisted) used in the
Endangered Species Act. Parameters considered
in determining if species within these categories
are of concern include population size, extent of
range, threats to habitat, and other factors. The
BCC should be consulted for details regarding the
assessment process (USFWS 2002).
Of the 278 bird species on the Long Lake NWR
Complex Bird List, 49 are included in the BCC
(Appendix B). Of these, 23 species are of concern
at all three scales (i.e., BCR 11, Region 6 of the
USFWS, National), three species (Prairie Falcon,
American Golden-Plover, and Dickcissel) are of
concern only at the Region 6 and National scales,
one species (Short-eared Owl) is of concern only
within BCR 11 and Region 6, and one species
(Hudsonian Godwit) is of concern within BCR 11
and nationally, but not at a regional scale (Appendix
B). The remaining species (n= 21) are of concern at
only one scale (National = 15, USFWS Region 6 =
2, BCR = 4).
North American Waterfowl Management Plan.
The national goals set forth in the 1998 update of
the North American Waterfowl Management Plan
(NAWMP) include: (1) maintaining the current
diversity of duck species throughout North America
and achieving a continental breeding population
of 62 million ducks (mid-continent population of 39
million) during years with average environmental
conditions, which would support a fall flight of 100
million, (2) reaching or exceeding mid-continent
populations for 10 individual species, including
Gadwall, American Wigeon, Mallard, Blue-winged
and Cinnamon teal, Northern Shoveler, Northern
Pintail, Green-winged Teal, Canvasback, Redhead,
Greater and Lesser scaup, and (3) attaining an
American Black Duck mid-winter population
index of 385,000. The target populations for those
species occurring on lands comprising the Long
Lake NWR Complex are presented in Appendix B.
The plan also establishes objectives for six goose
species, three Trumpeter Swan populations, and
two Tundra Swan populations. Of these, relevant
objectives include reducing all five populations of
Canada Geese that migrate through the central
flyway and reducing mid-continent populations of
Snow and Greater White-fronted geese to 1,000,000
and 600,000, respectively. The plan also sets forth
objectives to increase the interior population of
Trumpeter Swans to 2500 and slightly reduce the
eastern population of Tundra Swans to 80,000
(Appendix B). Finally, habitat objectives for the
entire United States include protection of 2,856,785
ha, restoration of 1,249,352 ha, and enhancement of
2,922,126 ha (NAWMP, URL http://northamerican.
fws.gov/NAWMP/images/update98.PDF).
Partners In Flight North American Landbird
Conservation Plan. The North American Landbird
Conservation Plan (NALCP) is a synthesis of
priorities to guide national and international
conservation actions of 448 native landbirds from
45 families that breed in the United States and
Canada (Rich et al. 2004). Each species is assigned
a score ranging from one (low vulnerability) to five
(high vulnerability) for six factors (population size,
breeding distribution, nonbreeding distribution,
threats to breeding, threats to nonbreeding, and
population trend) (Rich et al. 2004). In addition, a
Stewardship List was developed based on avifaunal
biomes in North America. These biomes were
delineated using cluster analyses to identify groups
of BCRs that share similar avifaunas. For each
biome, Stewardship Species are those species that
have a proportionately high percentage of their
world population within a single region during
either the breeding or wintering season. The lands
comprising the Long Lake NWR Complex are in the
Prairie Avifaunal Biome, which is composed of BCRs
11, 17 - 19, and 21 - 23. Almost 40% of the species on
the Partners in Flight Watch List due to declining
population trends or high threats occur in this biome
(Rich et al. 2004, URL http://www.partnersinflight.
org, URL http://www.rmbo.org/pif/pifdb.html).
The Watch List and Stewardship List of
continentally important species in the United States
and Canada currently include 100 and 158 species
(66 species on the Stewardship List also occur on the
Watch List), respectively (Rich et al. 2004). Within
the Prairie Avifaunal Biome, there are 21 and seven
species of continental importance on the Watch
List and Stewardship List, respectively. Of these 28
species, 22 (Watch List = 16 species, Stewardship
List = six species) have been recorded as occurring
on the Long Lake NWR Complex (Appendix B).
The recommended conservation action for three of
these species is immediate action (Greater Prairie-
Chicken, Baird’s and Henslow’s sparrows), whereas
11 species (Swainson’s Hawk, Short-eared Owl, Red-headed
Woodpecker, Willow Flycatcher, Sprague’s
Pipit, Lark Bunting, Grasshopper and Harris’s
sparrows, Chestnut-collared Longspur, Dickcissel,
and Rusty Blackbird) require management and six
species (Sharp-tailed Grouse, American Tree and
Nelson’s Sharp-tailed sparrows, and McCown’s,
Lapland, and Smith’s longspurs) necessitate long-term
planning and responsibility.
14 A Preliminary Biological Assessment of Long Lake National Wildlife Refuge Complex, North Dakota
Shorebird Conservation Plan. The lands of the
Long Lake NWR Complex are in the Northern
Plains/Prairie Pothole Region (NP/PPR), an area
that encompasses more than 810,666 km2 and
includes all or portions of seven states and two
BCRs (Prairie Potholes, Badland and Prairies)
(Skagen and Thompson 2003). The landscape is
characterized by rolling prairie interspersed with
millions of depressional wetlands, intermittent and
permanent streams and rivers, and agriculture.
Thirty-six shorebird species occur in the NP/PPR,
35 of which have been observed on or adjacent to
Long Lake NWR. Of the 13 species known to breed
in the region, nine species (Piping Plover, Killdeer,
American Avocet, Willet, Spotted and Upland
sandpipers, Marbled Godwit, Wilson’s Snipe, and
Wilson’s Phalarope) have been documented as
nesting on Long Lake NWR and five of these species
(Piping Plover, American Avocet, Upland Sandpiper,
Marbled Godwit, and Wilson’s Phalarope) are listed
as species of regional concern (Appendix B). The
Piping Plover also is listed as threatened under
the Endangered Species Act. The NP/PPR also is
a major migration route for western hemispheric
shorebirds. In addition, the NP/PPR is considered
particularly important for 10 migrant shorebirds
(American Golden-Plover, Semipalmated Plover,
Lesser Yellowlegs, Semipalmated, White-rumped,
Baird’s, and Pectoral sandpipers, Dunlin, Stilt
Sandpiper, and Long-billed Dowitcher). Although
none of these species is considered a regional species
of concern, the provision of adequate stopover
habitat is a regional priority. Nearly 27% of small
shorebirds (total body length < 190 mm in the mid-continent
region migrate through the NP/PPR in
spring, whereas > 22% of medium-sized shorebirds
utilize the NP/PPR during fall migration (Appendix
B; Skagen and Thompson 2003; U.S. Shorebird
Conservation Plan, URL http://shorebirdplan.fws.
gov/RegionalShorebird/downloads/NORPLPP2.
doc).
Waterbird Conservation Region. The lands of
the Long Lake NWR Complex are located in the
Northern Prairie and Parkland Region (NPPR) of
the North American Waterbird Conservation Plan
(NAWCP). The boundaries of the NPPR occur in
two disjunctive areas that include four Canadian
provinces and five states in the U.S. The NPPR
boundary is similar to the BCR 11 boundary, but also
includes portions of BCRs 6 and 10. The NPPR also
overlaps areas covered by the Prairie Habitat Joint
Venture in Canada and the Prairie Pothole Joint
Venture (PPJV) in the U.S.
The NAWCP focuses on members of eight
orders and 22 families of birds, including coastal
waterbirds, wading birds, and marshbirds
(Waterbird Conservation for the Americas, URL
http://www.waterbirdconservation.org/waterbirds/).
There are 71 species of waterbirds that occur in
the NPPR; 24 colonial and 15 non-colonial species
that breed, and an additional 32 species that occur
as migrants or winter visitors. Of these 71 species,
59 species (33 breeding, 7 regular migrants, and 19
casual species) occur in North Dakota. Twenty of
the 33 breeding species and one (Whooping Crane)
of seven regular migrant species that occur in
North Dakota have been documented on the Long
Lake NWR (Appendix B). The conservation status
of the 20 breeding species at Long Lake NWR
includes six that are of high concern (Horned and
Western grebes, American Bittern, Yellow Rail,
Franklin’s Gull, and Black Tern), four of moderate
concern (Eared Grebe, Black-crowned Night-Heron,
Virginia Rail, and Common Tern) and 10 species
considered low risk (Beyersbergen et al. 2004, URL
http://birds.fws.gov/waterbirds/NPP/). Although
not documented as current breeders, Long Lake
NWR has documented the occurrence of two species
(Whooping Crane and Least Tern) that are listed for
protection under the Endangered Species Act.
Prairie Pothole Joint Venture. The lands
comprising the Long Lake NWR Complex are
within the boundaries of the PPJV of the NAWMP.
Joint ventures were originally conceived by the
USFWS in 1986 to implement the NAWMP.
Established in 1989, the goal of the PPJV is to
increase waterfowl populations through habitat
conservation projects that improve natural diversity
(diversity defined as an appropriate mix of plant
and animal communities that can be sustained in
association with profitable agriculture). However,
in addition to waterfowl, many joint ventures
(including the PPJV) are now incorporating an “all
bird” approach. There are 225 species that breed in
the PPR, including several grassland species (e.g.,
Lark Bunting, Grasshopper and Baird’s sparrows,
Dickcissel, and Bobolink) that have declined
significantly over the past three decades (U.S.
Prairie Pothole Joint Venture 1995). The objectives
established for the PPJV include (1) conserve
habitat capable of supporting 6.8 million breeding
ducks by the year 2001 and (2) stabilize or increase
populations of declining wetland and grassland-associated
wildlife species in the PPR, with special
emphasis on non-waterfowl migratory birds (U.S.
Prairie Pothole Joint Venture 1995). Habitat
objectives in the PPR include protection of 765,486
ha, restoration of 301,456 ha, and enhancement of
1,485,026 ha (URL http://northamerican.fws.gov/
NAWMP/images/update98.PDF).
15
Approach
The USFWS is involved in the management of more
than 607,000 ha in North Dakota (Byersbergen et al.
2004). However, many of these areas are small and
embedded within a larger landscape that has been
greatly modified by past land uses and management.
In North Dakota, agriculture represents the
primary land use, and one consequence of this
modification has been the fragmentation of the
prairie landscape into smaller parcels that has
negatively impacted many regional and local faunal
communities (Samson 1980, Johnson and Temple
1986, Knopf and Samson 1995). For example, 55
species from the Great Plains currently are listed
as threatened or endangered, and an additional
728 species represent potential additions to this list
(Flores 1995). In addition to biodiversity, however,
other important natural resource challenges also
are emerging. Past and current land uses have
negatively impacted air and water quality, water
availability, floodwater storage, and a host of other
ecosystem services (Huntzinger 1995, Krupa and
Legge 1995). Although often portrayed as separate
entities, these values are interrelated and all are
determined by ecosystem processes. For example,
the planting of non-native vegetation to reduce soil
erosion and improve water quality also directly
influences habitat suitability for different fauna.
Therefore, prior to implementing management
actions, a comprehensive evaluation of potential
changes to current ecosystem processes must be
undertaken to fully understand the implications of
different strategies. This is particularly important
today because an increasingly diverse group of
stakeholders with different attitudes and desires
are participating in natural resource management
decision making. This does not imply that all
ecosystem services must be provided on a single
NWR; rather, it suggests pertinent information on
all aspects of ecosystem services be evaluated to
maximize the probability that stakeholders with
different backgrounds and interests understand
the full range of potential trade-offs. For example, a
primary purpose of the Long Lake NWR Complex
is the provision of habitat for migratory birds and
other wildlife. However, the NWRSIA (and internal
USFWS guidance documents and policies) also
stresses the importance of biotic integrity and
ecosystem health. Thus, the impact of planned
management actions on these components, as
well as those valued by other agencies and private
landowners, should be considered.
Understanding processes should be a key factor
in natural resource management decisions. This
can only be accomplished by also considering the
formation and historical context of landscapes
(Jensen et al. 1996, Swanson et al. 1988) because
the success of management actions is constrained
by the properties of the land being managed. This
is particularly true in the Great Plains because
the environment is easy to alter, yet can collapse
quickly (Flores 1995). The authors have termed
this perspective the concept of “ecological fit” and
defined it as follows: the idea that the health and
sustainability of ecosystems depends on how well
management acts are coordinated with acts of
nature. The principal tenets of this concept are (1)
ecosystem function depends on synergistic processes
involving both uplands and wetlands, (2) a given
land unit (e.g., wetland basin) can undergo dramatic
changes in structure and function in relation
to short- and long-term acts of nature, and (3)
processes are interrelated; thus, any action intended
to alter a specific function may have unintended
results.
The following evaluation is based on the tenets of
ecological fit. However, Slade and Florence Lake
NWRs were not investigated in detail during the site
visit and little relevant information can be provided
regarding the current condition of system function
and structure. Thus, information gleaned from the
few sites visited on Slade and Florence Lake NWRs
is used throughout the remainder of this document
to draw comparisons with Long Lake NWR.
A review of records for each NWR revealed that
much information pertaining to the results of past
management actions has been recorded, but details
regarding impacts to abiotic factors (e.g., soils,
water quality) often are lacking or incomplete.
Thus, it is not possible to arrive at definitive
conclusions regarding how past management actions
have altered the systems encompassing each of
the NWRs. This is not surprising given that the
importance of these factors to management is only
beginning to be understood and applied. Therefore,
general information contained in the literature, in
combination with information provided Complex
staff, is used to identify potential challenges that
the planning team should consider when developing
the CCP. The intent is not to advocate an attempt
to return the land to pre-European settlement
conditions. This is unrealistic given the many
perturbations to the system. Rather, the intent
is to transfer information necessary to develop
Biological Assessment
16 A Preliminary Biological Assessment of Long Lake National Wildlife Refuge Complex, North Dakota
an understanding of current system function for
the purpose of assisting the Complex staff in the
development of a management program that will
achieve the goals of the Long Lake NWR Complex,
adjacent landowners, and society for productive and
sustainable natural resource benefits.
Current Conditions
Hydrology. Historically, Long Lake was part of the
ancestral Cannonball River. Fine materials (clays
and silts) transported by glacial meltwater settled in
areas of diminished flow velocities resulting in areas
with relatively impervious soils that stored large
quantities of water. In many cases (e.g., Long Lake),
these areas were sited in topographically low areas
and functioned to capture some water transported
through the valley. Following glacial retreat and
subsequent warming, obstructions (e.g., ice dams)
blocking valleys disappeared and water in the fluvial
system encompassing Long Lake was transported
through a network of channels to the Missouri River.
However, topographically low areas such as Long
Lake remained and accumulated water periodically.
The primary hydrologic input was surface water
(e.g., precipitation, runoff), but ground water
movement through adjacent terraces also influenced
lake hydrology and chemistry. Although speculative,
during years of low total inflow, surface water likely
was not discharged from these sites and was lost
only by evaporation and transpiration. In years of
high inflows, however, surface waters increased
above a natural sill and water was discharged
downstream. The variable surface water inputs that
occurred seasonally and annually, in combination
with topography (elevation ranges from 521.2 to
523.0 m above mean sea level [msl]) and ground-water
chemistry, resulted in Long Lake being
a relatively shallow, alkaline lake that exhibited
dynamic water-level fluctuations.
Although the valley encompassing Long Lake NWR
retains many historic features, the area has been
modified by both on-going natural processes and
anthropogenic forces. Perhaps the greatest change
that has impacted Long Lake NWR is hydrologic
alteration. Surface water, which enters Long Lake
via Long Lake Creek (~68%) and runoff from
surrounding uplands (~32%), remains the primary
hydrologic input to Long Lake and water is still
discharged from Long Lake to the Missouri River
via Apple Creek when surface water exceeds a
certain threshold. However, dike construction and
altered land-use patterns in the watershed likely
have altered the quantity, timing, and frequency
of water inflows and outflows. Limited information
documenting hydrologic alterations was located
for the watershed; thus, only information for
Long Lake NWR improvements obtained from
staff is provided. Following purchase in the 1930s,
the USFWS estimated that the natural outlet of
Long Lake was 522.2 m above msl. During 1936
and 1937, the Civilian Conservation Corps (CCC)
constructed three dikes (denoted as A, B, and C)
across Long Lake to form three units and built
several small dams to trap water in coulees entering
Long Lake. Several modifications to the lake dikes
(e.g., increased height and addition of water control
structures and spillways) were made during the
1940s, but two of the dikes (B and C) washed out
in 1950. In 1954, all three dikes were rebuilt to an
elevation of 524.3 m above msl and equipped with
spillways. The spillway in A Dike located at the
west end of Unit 1 was constructed at an elevation
of 523.0 m above msl, whereas the spillways in B
Dike (separating Unit 1 and Unit 2) and C Dike
(separating Unit 2 and Unit 3) were constructed at
an elevation of 523.2 m above msl (GAK). Since 1950,
additional dikes have been constructed adjacent
to Long Lake to capture surface water that enters
from natural drainage paths originating in the
uplands. In many cases (e.g., Unit 2 Marsh), these
impoundments can be flooded either by natural
runoff or by transporting water from Long Lake
via gravity flow, but dewatering is dependent on
evapotranspiration. Currently, the staff can manage
water in seven impoundments (three units of Long
Lake and four impoundments) on Long Lake NWR.
The specific hydrologic impacts of dike construction
are difficult to determine due to limited on-site
information. However, the construction of dikes
across the lake obstructed water movement within
the original lake bed. Lake bathymetry data were
not located, but observation suggests the dikes
were constructed across the natural elevation
gradient. Thus, the pattern and timing of flooding in
different portions of Long Lake was altered because
water from Long Lake Creek was sequentially
impounded behind each dike until a sufficient volume
accumulated to discharge water over the spillway
into the next unit. In contrast, the historic flooding
pattern was determined by natural elevation
gradients throughout the entire lake basin (e.g.,
water entering Long Lake pooled first in lowest
areas throughout the basin). Second, spillways were
constructed to heights greater than two feet above
the elevation of the historic lake outlet. Therefore,
the potential depth of flooding was increased.
Available inflow records indicate Long Lake
Creek is a perennial stream that exhibits sporadic
flows. Thus, although the creek represents a
reliable source of water, the volume of water is not
predictable. For example, no water was discharged
over the spillway in A Dike in 13 of 25 years between
1963 and 1987 (GAK). During this period, inflows
from Long Lake Creek ranged from 895 to 5836 ha-m
(average = 2253 ha-m). In contrast, during years
when water was discharged over A Dike, inflows
ranged from 1862 to 12,506 ha-m (average = 6235
ha-m). Coupled with the requirement to flood units
sequentially, these data, although imprecise, suggest
land comprising Unit 1 is flooded more frequently
and to a greater extent than would occur naturally,
whereas some land comprising Unit 3 is flooded less
frequently and for shorter time periods compared
to historic conditions. For example, Unit 3 was dry
by mid-August in six of the 13 years that no water
was discharged over the spillway in A Dike. During
this period, the surface flooding recorded in Unit
17
3 likely resulted from discharge of surface water
from several large coulees that drain surrounding
uplands and discharge directly into Units 2 and
3. The amount of water entering each unit is not
known, but staff estimated that Long Lake Creek
represented only 68% of the surface water input. If
correct, the remaining 32% of runoff originates from
other sources such as coulees that drain surrounding
uplands and discharge directly into each unit. In
some years, this input could be substantial. For
example, during the period 1963 to 1986, annual
precipitation recorded at Long Lake NWR ranged
from 23.6 to 55.9 cm and averaged 40.8 cm during
years when water was not discharged over the
spillway in A Dike. However, this information does
not adequately represent current inputs because
additional dikes have been constructed across some
of these coulees since 1986 (e.g., Unit 2 Marsh
completed in 1987). Thus, the amount of surface
inflows to Long Lake via these drainage paths has
likely been reduced.
In general, all dikes on Long Lake NWR were
installed to improve water management flexibility.
However, a primary purpose for separating Long
Lake into units was to better manage water to
prevent botulism outbreaks (USFWS 1988). Thus,
many of the aforementioned hydrologic alterations
caused by dikes were intentional. For example, the
goal of water management from 1944 to 1959 was to
fill Unit 1 to 523.0 m, Unit 2 to 522.9 m, and Unit 3
to 522.7 m above msl. This strategy was considered
highly effective for Units 1 and 2, but Unit 3 could
not reliably be stabilized and frequently went dry.
Between 1960 and 1987, the water management
strategy basically remained the same for Units 1 and
2, but Unit 3 was maintained in as dry a condition as
possible. Although Unit 3 was dry nine of these 28
years, records indicate that the water management
capability was inadequate to reliably meet these
goals (USFWS 1988), which indicates that natural
climate cycles still influenced water-level fluctuations
to some extent. The current strategy is based on
water elevations in the spring; if water levels do not
exceed a certain threshold (522.9 m msl), Unit 3 is
kept as dry as possible; otherwise Unit 3 is flooded
to the extent possible.
The success of these water management strategies
in reducing botulism outbreaks is difficult to
interpret. Prior to initiating water management in
1944, the estimated total avian deaths from botulism
between 1937 and 1943 exceeded 375,000 and
ranged from 75 in 1938 to 145,000 in 1941 (Figure
2). In contrast, the total estimated loss between
1944 and 2004 was only 82,953 birds (range = 0 to
18,700) (McEnroe 1986, USFWS 1988, USFWS
unpublished data). This suggests that developing
the ability to control water levels provided some
ability to ameliorate the incidence and extent of
botulism outbreaks. However, numerous factors
are involved in the progression from the initiation
and propagation phases to large botulism outbreaks
(Wobeser 1997). Further, there are likely many
alternative pathways that lead to an outbreak;
thus, determining effective management practices
is hampered by an incomplete knowledge of the
environmental factors that precipitate outbreaks
(Wobeser and Bollinger 2002). In general, it has been
recommended that control efforts need to focus on
three important factors: (1) fluctuating water levels
during hot summer months, (2) an abundance of
flies, and (3) presence of animal carcasses necessary
for toxin production (Lock and Friend 1989). Thus,
although it is plausible that water management
contributed to prevention, other factors likely were
involved as well. For example, factors reported as
potentially signifying an increased risk of a botulism
outbreak include increasing temperature, increasing
invertebrate abundance or biomass, and decreasing
turbidity (Rocke et al. 1999). Unfortunately, data
on botulism deaths and environmental factors
for each individual unit were not located; thus,
any conclusions regarding the effects of water
management would be extremely speculative.
Sediment and Nutrient Dynamics. Regardless of
how effective water management strategies have
been with respect to controlling the incidence and
extent of botulism outbreaks, human perturbations
have likely impacted other processes that determine
system structure and function, including the
interrelated factors of sediment dynamics and
nutrient loads. These factors are important
because they affect both upland and wetland plant
community dynamics. Inorganic nutrients provide
the chemical constituents that form the basis of
the entire food chain. Common nutrients needed in
large quantities for cell development include oxygen,
carbon, phosphorous, silica, sulfur, iron, magnesium,
calcium, potassium, nitrogen, and hydrogen,
whereas manganese, molybdenum, copper, zinc, and
cobalt are minor nutrients that may occasionally be
in short supply (Salisbury and Ross 1978, Goldman
and Horne 1983, Table 11). Ionic compounds (e.g.,
sodium, potassium, and chloride) affect ion exchange
at the surface of cell membranes, whereas toxic
compounds can negatively impact nutrient cycling
by causing mortality of plants or animals. Some
inorganic compounds (e.g., copper and zinc) can
act either as toxicants or as growth stimulators. In
contrast, organic compounds tend to occur in small
quantities in natural systems and some (e.g., humic
acids and citrate) can alter the chemical state of
water by changing the ionic state of metals that
might otherwise be toxic.
The primary factors determining daily, seasonal,
and long-term cycles of major elements in natural
systems are rainfall, evaporation, erosion and
solution, sedimentation, and biological components
of the watershed (Goldman and Horne 1983).
These factors, in turn, are influenced by parent
material, climate, topography, and vegetation
cover in the watershed. The extent that human
perturbations have altered sediment dynamics and
nutrient loads on each NWR cannot be determined
directly because records are lacking or sporadic.
However, soil organic matter greatly influences
productivity by functioning as a binding agent
18 A Preliminary Biological Assessment of Long Lake National Wildlife Refuge Complex, North Dakota
that aids soil structure formation and stability,
which is critical to maintaining adequate water
infiltration and potential water storage (Peterson
and Cole 1995). In addition, organic matter also is
a primary requisite for retaining certain nutrients,
particularly nitrogen. Therefore, loss of surface
horizons in terrestrial habitats reduces nitrogen
availability and, if sufficient losses occur, results
in reduced plant productivity (Peterson and Cole
1995). Thus, concerns associated with past and
current agricultural practices are not limited only
to the fragmentation and loss of native vegetation
that reduces habitat suitability for native wildlife.
Rather, these activities also can accelerate soil
erosion that can reduce the potential productivity of
sites suffering soil loss, as well as negatively impact
sites receiving increased sediment overburden
(Kothmann 1995).
The extent that soil erosion and nutrient
redistribution has occurred on lands encompassed
by all three NWRs is unknown. However, 87% of
improved prairie farmlands in the Great Plains are
characterized as exhibiting medium to high erosion
risk (Sopuck 1995) and the estimated average
annual sheet and rill erosion on non-federal rural
land for North Dakota in 1987 was 0.8 tons per ha
in cropland, 0.2 tons per ha in pastureland, and 0.4
tons per ha in rangeland, whereas the estimated
average annual wind erosion on cultivated and
non-cultivated cropland was 1.7 tons per ha and
0.08 tons per ha, respectively (Kothmann 1995).
Thus, it is likely that some soil erosion has occurred,
particularly in areas with steeper slopes that have
a history of cropping. In contrast, erosion is of
less concern in areas of lesser impact. We provide
two examples to illustrate this point. The first is
from soil cores collected at Florence Lake NWR in
an area that has been minimally impacted by past
land uses. A core collected in a seasonal wetland
suggested the presence of a deep A horizon on the
surface and an argillic B horizon at about 16 in (40.6
cm). Further, soils were not mixed and exhibited
a structure characteristic of a relatively unaltered
wetland substrate. A second core collected at the top
of a hill adjacent to this wetland also exhibited a well
developed A horizon to a depth of 12.7 to 15.2 cm and
an underlying B horizon, suggesting minimal soil
erosion has occurred.
The other example is from soil cores collected in
Unit G7 and Unit 2 Marsh of Long Lake NWR.
Based on the county soil survey, soils in Unit G7
exhibit a sand mantle and a past land use history
that may have included farming. The soil core
collected near a knoll in this unit indicated that
soil structure was generally lacking. The top 10 cm
contained little organic material and was assumed
to represent the A horizon and the underlying B
horizon (10 - 20 cm) contained a mix of sand with
small amounts of clay. The second core collected
at the toe-slope of the same hill also indicated
minimal soil structure, but the A horizon was at
least 20 cm in depth and contained substantially
more organic matter. Although not definitive, these
two cores suggest that soil from the slopes has been
transported (i.e., eroded) to surrounding low areas.
In conventional agriculture, the solution to soil
degradation has consisted of using biological and
chemical inputs (e.g., fertilizers) to replace nutrient
losses (Sopuck 1995) and planting crop varieties
adapted for growth under altered conditions.
However, this complement of options often is not
available when attempting to restore native prairie
vegetation. First, the term native refers to plants
that originally occupied the site of interest; thus
planting new “varieties” is not plausible even if they
were available. Second, unlike crop monocultures,
mixed-grass prairie consists of numerous grass and
forb species that exhibit a non-random distribution
determined by abiotic factors (e.g., soil topography,
climate). Therefore, application of fertilizer will
not overcome the problems associated with the
differential loss of organic matter. Finally, frequent
cultivation to control introduced tame grasses and
invasive plants cannot be performed simultaneously
with the reestablishment of native grasses and forbs
without causing mortality of desirable species.
In contrast to terrestrial sites, primary productivity
of many disturbed wetlands often is reduced due
to the excessive accumulation of sediments and
nutrients (Rybicki and Carter 1986, Dieter 1991,
Hartleb et al. 1993, Jurik et al. 1994, Wang et al.
1994, Gleason and Euliss 1998, Gleason et al. 2003).
In terms of quantity, sediment has become the
major pollutant of wetlands, lakes, estuaries, and
reservoirs in the United States (Baker 1992) and
many river systems are now considered degraded
(Longcore et al. 1987, Grue et al. 1989). The greatest
causes of altered water chemistry are contamination
from agriculture, road construction, and industry
(Ulrich and Pfeifer 1976, Swanson et al. 1988, Euliss
et al. 1999) because these activities can alter the
distribution of soils and sediments, which can act as
both a sink and source for water quality constituents.
In some cases, productivity can be affected by an
imbalance in a single element. For example, salinity
can directly inhibit germination and growth of
plants (Swanson et al. 1988, Kantrud et al. 1989) and
excessive additions of phosphorous (e.g., fertilizer
runoff) can lead to extensive algal blooms that
inhibit growth of some submerged aquatic plants
(Robel 1961, Kullberg 1974, Swanson et al. 1988). In
other situations, however, water-borne elements can
act alone or synergistically to affect productivity. For
example, salinity can exacerbate boron toxicity in
several plant species (Wimmer et al. 2003). Further,
suppression of primary production often negatively
impacts secondary productivity. For example,
salinity can influence invertebrate composition
directly by affecting physiology (Newcombe and
MacDonald 1991, Euliss et al. 1999) or indirectly
by affecting habitat structure and foods (Krull,
1970, Wollheim and Lovvorn 1996). Other examples
include documented reports that high concentrations
of suspended silt and clay are toxic to zooplankton
(Newcombe and MacDonald 1991)
19
and agrichemicals can cause significant mortality of
aquatic invertebrates (Borthwick 1988).
As mentioned previously, natural systems exhibit
plasticity to fluctuations in water quality and
sediments. For example, natural concentrations
of dissolved solids within a single closed-basin
wetland can fluctuate from fresh to extremely saline
depending on climatic variables that influence
hydrology (Swanson et al. 1988, LaBaugh 1989).
Historically, the water chemistry of Long Lake
likely was dynamic given that it was part of a
riverine system characterized by sporadic flows that
resulted in fluctuating lake levels. Intact upland and
floodplain vegetation attenuated surface runoff and
soil erosion, and acted as a filter to limit the amount
of sediment that entered the creek channel and
surrounding coulees. During periods of extended
low flow, the volume of water entering Long Lake in
some years was insufficient to overtop the natural
outlet (elevation = 522.2 m); thus, Long Lake
represented a terminal point of water collection.
When this occurred, discharge of water downstream
of Long Lake did not occur and water loss occurred
only by evapotranspiration. This would tend to
cause an increase in the concentration of organic
and inorganic compounds. In contrast, during
years of higher flow, the volume of water entering
Long Lake would be sufficient to breach the natural
outlet and water would be discharged downstream.
During these periods, the concentration of organic
and inorganic compounds in surface waters of Long
Lake would decrease due to dilution and transport
downstream. Unfortunately, data from USGS
gauge stations above and below Long Lake are only
available for a brief period in the late 1980s and early
1990s; therefore, it is not possible to evaluate the
frequency with which these two extremes occurred.
Nonetheless, the concentration of nutrients and
elements in the waters of Long Lake likely was
dynamic because variable surface water inputs
resulted in the occasional concentration and dilution
of nutrients and other elements as the region
experienced climate extremes ranging from drought
to deluge.
However, alterations that affect fundamental
processes (e.g., hydrology, water chemistry,
sediment dynamics) often alter system tolerance
and can result in significant shifts in plant and
invertebrate communities. River systems are
concentration points for sediments and chemical
constituents bound to sediments because they
collect runoff from surrounding uplands. Thus,
sediment transport and deposition is a naturally
occurring process that affects formation, structure,
and function of wetlands (Saucier 1994). Prior to
human alteration, areas of transport and deposition
tended to change temporally in response to channel
characteristics that influenced flow velocities. Long
Lake likely represented an area of accumulation
within the watershed, but dynamic flow patterns
resulted in periods of concentration and dilution.
Further, the amount of sediment and bound
constituents entering the system was within normal
bounds and excess nutrients (e.g., nitrogen and
phosphorus) could be processed without risk to
long-term productivity. For example, wetlands
may be capable of removing 70 to 90% of nitrogen
entering a system (Gilliam 1994) and 20 to 100%
of metals, depending on wetland type, individual
site characteristics, and metal type (Taylor et al.
1990, Gambrell 1994). However, construction of
dikes within the floodplain on Long Lake has likely
contributed to altered sediment and chemical
deposition patterns by changing flow velocities
and other hydrologic parameters, including the
frequency, depth, and time of flooding. Further, the
type of alteration differs depending on the location
of one dike relative to other dikes. For example,
the upstream unit (Unit 1) likely receives a greater
volume of water annually and discharge over the
spillway occurs more frequently compared to the
dike separating Unit 2 from Unit 3. As a result,
the frequency of flushing flows likely decreases
sequentially from Unit 1 to Unit 3. Coupled with
potential increases in the amount of material
entering the system, it is possible that sediment
loads and concentrations of certain constituents vary
within each unit.
Information on the rate of sediment accretion
in wetlands was not located, but Complex staff
indicated that palustrine wetlands surrounded by
croplands likely have accrued sediment. During
the site visit, soils inspected in a seasonal wetland
on Slade NWR and in Unit 2 Marsh on Long Lake
NWR also suggested that sediment accrual has
occurred and turbid conditions in the Long Lake
units suggested the presence of some unconsolidated
sediments. In addition, a few historic records were
located that compared water chemistry on either
side of a single dike on Long Lake. In 1969, the
chemistry on the east side of an unspecified road
exhibited greater total alkalinity and specific
conductivity and increased concentrations of sulfate
chloride sodium, and potassium compared to the
water on the west side of the same road (Swanson
et al. 1988). Similar observations were recorded
during the site visit; the specific conductivity of
water in Units 1, 2, and 3 exhibited increasing values
of 1910, 2600, and 4200 μS per cm, respectively.
Although these limited data suggest changes in
sediment dynamics and water chemistry, it is not
possible to determine the extent that these observed
differences are due to natural variation in climate
(LaBaugh and Swanson 2004) as opposed to long-term
changes resulting from dike construction and
altered land use patterns.
Information also is lacking to quantify the extent
that human influences have altered dynamic
fluctuation of nutrients (e.g., nitrogen, phosphorous)
and other elements (e.g., mercury, boron, arsenic) in
the Long Lake Units. However, relative to historic
conditions, management actions have increased
water storage volumes up to three feet above the
natural sill in the three Units. Retaining more
water in the Units than would occur naturally,
in combination with altering the frequency of
20 A Preliminary Biological Assessment of Long Lake National Wildlife Refuge Complex, North Dakota
flushing flows, will increase the overall potential for
accumulation of various ions, elements, and other
dissolved solids via evaporative processes. This
potential can be demonstrated by using information
on specific conductance and estimates of average
annual lake evaporation. For example, total dissolved
matter can be estimated from specific conductance
data by multiplying by an empirical factor that
typically varies from 0.5 to 1.0 (Figure 3). Ideally,
the relationship between specific conductance
and total dissolved matter is determined for a
particular location. However, since this information
is lacking, we used the factor 0.65 suggested by
Rainwater and Thatcher (1960) because it provides
a good approximation of total dissolved matter data
presented in Table 3. Using this factor, estimates
of total dissolved matter were within 3% (range
= 1 to 6%) of those reported in Table 3. Given this
relationship, each ha-m of water with a specific
conductance of 1000 μS per cm that was stored and
evaporated would result in the accumulation of 7.33
tons of total dissolved matter. When extrapolated
to the area of each Unit (Unit 1 = 507.5 ha, Unit 2 =
827.6 ha, and Unit 3 = 5369.2 ha), the evaporation
of 30.5 cm of water from all Units combined would
result in the accumulation of 14,987.8 tons of
dissolved matter (e.g., 6704 ha * 7.33 tons * 0.305).
However, the amount of dissolve matter actually
accumulated in each Unit will vary depending on
evaporation rates (Figure 4). Given that the average
annual lake evaporation for this region can exceed 91
cm (Shjeflo 1968), the above estimate is considered
conservative.
Based o

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U.S Fish & Wildlife Service
A Preliminary Biological
Assessment of Long Lake
National Wildlife Refuge
Complex, North Dakota
Biological Technical Publication
BTP-R6006-2006
U.S Fish & Wildlife Service
A Preliminary Biological
Assessment of Long Lake
National Wildlife Refuge
Complex, North Dakota
Biological Technical Publication
BTP-R6006-2006
Murray K. Laubhan1
Robert A. Gleason1
Gregory A. Knutsen2
Rachel A. Laubhan3
N. H. Euliss, Jr.1
1 U.S. Geological Survey, Northern Prairie Wildlife Research Center
8711 37th Street SE, Jamestown, ND
2 U.S. Fish and Wildlife Service, Region 6, Long Lake National Wildlife Refuge
Complex, 12000 353rd Street SE, Moffit, ND
3 U.S. Fish and Wildlife Service, Region 6, Denver, CO
Cover image credit: Title: Canvasback Hen
Alternative Title: Aythya valisineria
Creator: Dewhurst, Donna
ii A Preliminary Biological Assessment of Long Lake National Wildlife Refuge Complex, North Dakota
Author Contact information:
Murray K. Laubhan, U.S. Geological Survey, Northern Prairie Wildlife Research Center, 8711 37th St. SE,
Jamestown, ND 58401. Phone: (701) 253-5534, Fax: (701) 253-5553, e-mail: Murray_Laubhan@usgs.gov.
Robert A. Gleason, U.S. Geological Survey, Northern Prairie Wildlife Research Center, 8711 37th St. SE,
Jamestown, ND 58401. Phone: (701) 253-5546, Fax: (701) 253-5553, e-mail: Robert_Gleason@usgs.gov.
Gregory A. Knutsen, U.S. Fish and Wildlife Service, Region 6, Long Lake National Wildlife Refuge Complex,
12000 353rd Street SE, Moffit, ND, USA 58560. Phone: (701) 387-4397, e-mail: Gregg_Knutsen@fws.gov.
Rachel A. Laubhan, U.S. Fish and Wildlife Service, Region 6, Northern Prairie Wildlife Research Center, 8711
37th St. SE, Jamestown, ND 58401. Phone: (701) 253-5543, Fax: (701) 253-5553, e-mail: Rachel_Laubhan@
fws.gov.
N. H. Euliss, Jr., U.S. Geological Survey, Northern Prairie Wildlife Research Center, 8711 37th St. SE,
Jamestown, ND 58401. Phone: (701) 253-5564, Fax: (701) 253-5553, e-mail: Ned_Euliss@usgs.gov.
Recommended citation:
Laubhan, M. K, R. A. Gleason, G. A. Knutsen, R. A Laubhan, and Ned H. Euliss, Jr. 2006. A preliminary
biological assessment of Long Lake National Wildlife Refuge Complex, North Dakota. U.S. Department of
Interior, Fish and Wildlife Service, Biological Technical Publication, BTP R6006-2006, Washington, D.C.
For additional copies or information, contact:
Associate Editor: Wayne J. King
Regional Refuge Biologist
USFWS, Region 6
P.O. Box 25486
Denver Federal Center
Denver, Colorado 80225-0486
iii
Table of Contents
Acknowledgements.............................................................................................................................................. vi
Summary...................................................................................................................................................................................1
Introduction..............................................................................................................................................................................2
Description...............................................................................................................................................................................3
Refuge Establishments and Authorities..............................................................................................................................3
Long Lake NWR.................................................................................................................................................... 3
Slade NWR.............................................................................................................................................................. 3
Florence Lake NWR.............................................................................................................................................. 3
Location and Formation..........................................................................................................................................................3
Landform and Topography......................................................................................................................................................4
Soils...........................................................................................................................................................................................5
Climate......................................................................................................................................................................................6
Ground Water and Surface Water........................................................................................................................................6
Vegetation.................................................................................................................................................................................7
Wildlife Conservation...........................................................................................................................................................10
Long Lake NWR Complex.................................................................................................................................. 11
Bird Conservation Region................................................................................................................................... 12
Birds of Conservation Concern.......................................................................................................................... 13
North American Waterfowl Management Plan................................................................................................. 13
Partners In Flight North American Landbird Conservation Plan................................................................. 13
Shorebird Conservation Plan.............................................................................................................................. 14
Waterbird Conservation Region......................................................................................................................... 14
Prairie Pothole Joint Venture.............................................................................................................................. 14
Biological Assessment.........................................................................................................................................................15
Approach.................................................................................................................................................................................15
Current Conditions.................................................................................................................................................................16
Hydrology............................................................................................................................................................ 16
Sediment and Nutrient Dynamics..................................................................................................................... 17
Vegetation and Wildlife...................................................................................................................................... 20
Potential Information Needs............................................................................................................................. 21
Literature Cited......................................................................................................................................................................22
Appendix A. Scientific and common names of animals and plants mentioned in the text......................................42
Appendix B. Conservation status for avian species based on regional and national plans...................................51
Appendix C. ............................................................................................................................................................................55
Quantitative measurements of habitat structure reported in the literature that may be related to use by
select avian species: (a) vegetation height at nest sites or within breeding territories of
wetland nesting species, (b) water depth at nest sites or within breeding territories of wetland nesting
species, (c) water depth at foraging sites, (d) visual obstruction at nest sites or within breeding
territories of upland nesting species, (e) vegetation height at nest sites or within breeding territories of
upland nesting species, and (f) litter depth at nest sites or within breeding territories of upland nesting
species.
iv A Preliminary Biological Assessment of Long Lake National Wildlife Refuge Complex, North Dakota
List of Figures
Figure 1. Location of Long Lake, Slade, and Florence Lake National Wildlife Refuges, and associated
waterfowl production areas, in Burleigh, Emmons, and Kidder counties, North Dakota.................................. 38
Figure 2. Estimated annual number of avian deaths (waterfowl and other birds) due to botulism on Long
Lake National Wildlife Refuge, 1937-2004................................................................................................................ 39
Figure 3. Relationship between specific conductance (μS per cm) and dissolved matter (mg per L)................ 40
Figure 4. Estimated potential accumulation (tons) of evaporates per 30.5 cm of water that evaporates from
Units 1, 2, and 3 on Long Lake National Wildlife Refuge....................................................................................... 41
List of Tables
Table 1. General physical properties of soil associations occurring on Long Lake, Slade, and Florence
Lake National Wildlife Refuges................................................................................................................................ 27
Table 2. Properties of common soil series underlying wetland basins on Long Lake, Slade, and
Florence Lake National Wildlife Refuges................................................................................................................. 28
Table 3. Concentrations of select constituents in water from glacial drift in the vicinity of Long Lake,
Harker Lake, and Florence Lake in Burleigh and Kidder counties, North Dakota........................................... 29
Table 4. Distribution of wetland types in Burleigh and Kidder counties, North Dakota.................................... 30
Table 5. Area (ha) of cover classes on Long Lake National Wildlife Refuge in 2003........................................... 31
Table 6. Frequency of occurrence (%) of terrestrial plant associations based on 25-m belt transects in
Unit G-6 (n = 18 transects) and virgin sod units (Units G-4A, G-4B, G-4C, G-9A, and G-9B; n = 74
transects) on Long Lake and Florence Lake (n = 50 transects) National Wildlife Refuges in 2004 and
2002, respectively........................................................................................................................................................ 32
Table 7. Waterfowl breeding population estimates and recruitment rates on Long Lake National Wildlife
Refuge Complex (including the Wetland Management District), 1987-2004........................................................ 33
Table 8. Nest success on seven management units of Long Lake National Wildlife Refuge during 2002
and six Waterfowl Production Areas in the Long Lake Wetland Management District during 2001............... 34
Table 9. Number of colonial waterbird breeding pairs, number of colonies, and distribution of breeding
pairs among wetland probability classes on Long Lake National Wildlife Refuge during 2003....................... 35
Table 10. Relative abundance, estimated breeding pairs per 100 ha, and frequency of occurrence of 15
grassland/wetland edge nesting passerines on Long Lake NWR, 2001-2004...................................................... 36
Table 11. Internal tissue concentrations of essential elements that are considered adequate for most
higher plants (Salisbury and Ross 1978)................................................................................................................... 37
vi A Preliminary Biological Assessment of Long Lake National Wildlife Refuge Complex, North Dakota
Acknowledgments
Prior to writing the report, U.S. Geological Survey
personnel (Robert Gleason, Ned Euliss Jr., and
Murray Laubhan) were invited to a meeting (5
- 7 April 2004) with Long Lake National Refuge
staff (Paul Van Ningen, Gregory Knutsen, Natoma
Buskness, and Cheryl Jacobs) and U.S. Fish
and Wildlife Service Region 6 personnel (Linda
Kelly, Wayne King, Rachel Laubhan, and Adam
Misztal). The purpose was to become familiar with
certain National Wildlife Refuge lands, discuss
management opportunities and constraints, and
identify information that potentially could assist the
staff in developing a credible biological plan to guide
future management. These individuals contributed
significant time and insight regarding management
of the Long Lake National Wildlife Refuge Complex.
Thanks also to the following individuals for
providing reviews of an earlier draft: S. L. Jones, D.
G. Jorde, W. J. King, D. M. Mushet, J. D. Petty, A. J.
Symstad, and K. Torkelson.
Summary
This report represents an initial biological
assessment of wetland conditions on Long Lake
National Wildlife Refuge (NWR), Slade NWR,
and Florence Lake NWR that was conducted as
part of the pre-planning phase for development
of a Comprehensive Conservation Plan (CCP).
According to the 1997 National Wildlife Refuge
System Improvement Act (NWRSIA), decisions
guiding NWR management should be based on the
best available scientific information. Therefore, this
report attempts to integrate relevant information
from many different scientific disciplines (e.g.,
geology, hydrology, biology) to assist the U.S.
Fish and Wildlife Service (USFWS) in identifying
ecological constraints and opportunities imposed
by the land base being considered. The intent is
to provide information and ideas necessary for
evaluating the potential benefits and detriments of
management actions during the decision making
process that accompanies development of biological
goals and objectives.
Information in this report is based on a relatively
limited number of published articles, past notes, and
observations during a visit to Long Lake, Florence
Lake, and Slade NWRs. The authors only attempted
to locate sufficient relevant information necessary
to formulate more definitive ideas and provide
additional context. Thus, the information provided
below is incomplete and a more thorough synthesis
will be required. Further, interpretation of published
information can vary among individuals, and the
Long Lake NWR Complex (hereafter Complex)
staff is encouraged to review the documents cited
in this report. Many years of staff observation and
experience managing the Complex are invaluable to
ensuring that information used to make decisions
is applicable. Consequently, some sections contain
information that was not fully explored in the
evaluation section; however, the information was
retained because it may be useful as the Complex
staff and core CCP team examine different
management options. Finally, decisions regarding
management of the wetland community also require
integrating information from terrestrial lands that
impact wetlands (i.e. catchment). Although this may
seem simple and straightforward, this task often is
difficult because it frequently requires an iterative
approach to ensure that important issues that may
affect management of both wetlands and uplands
have not been omitted.
This report does not contain conclusions, nor does
it advocate any opinions (favorable or unfavorable)
regarding the biological program. Further, concepts
such as alternatives, goals, and objectives, are
not discussed. The core CCP team will address
these topics. Rather, it represents a summary that
hopefully will be used to focus future discussion
regarding biological data needs and approaches for
using this information to make decisions. Ultimately,
however, scientific information alone will not lead
to a definitive decision regarding future direction.
Also, biology is only one of many components that
must be considered in the evaluation. Therefore,
it is recommended that USFWS personnel
responsible for determining the future direction
of Complex management be consulted to establish
guidelines and agree on the approach that will be
used in evaluating the biological program prior to
proceeding.
A Preliminary Biological Assessment of Long Lake National Wildlife Refuge Complex, North Dakota
Introduction
The impetus for this report was passage of the 1997
NWRSIA that requires each NWR in the National
Wildlife Refuge System (NWRS) to develop a
CCP that includes goals and objectives that are
based on the best available science. To accomplish
this mandate, Region 6 of the USFWS contracted
with the Biological Resources Division of the U.S.
Geological Survey (USGS) to inspect wetland
habitats and synthesize available information
pertinent to the management of Long Lake, Slade,
and Florence Lake NWRs as part of a pre-planning
phase to guide development of a CCP. This report
represents the initial synthesis.
The brevity of the site visit did not allow for detailed
discussions between USGS and USFWS personnel,
but it did provide the opportunity to exchange
thoughts regarding the information needed to
evaluate the biological program. Thus, the ideas
contained within this report are of a general nature
and should be viewed as a collaborative effort that
involved the Complex staff. Additional work will
be required to objectively evaluate the biological
program, and this report should be viewed as an
initial effort to start this process. In addition, there
are alternative ways of approaching an evaluation
that would require different levels and types of
information. Therefore, the responsibility of the
USFWS is to review the report and other relevant
materials, discuss available options with appropriate
personnel, and determine if the identified
information needs and recommendations outlined
in this report are acceptable and represent the
preferred manner of proceeding.
General descriptive information on NWR
establishment, topography, climate, geology, soils,
vegetation, and wildlife is intended to provide a
brief background of these three NWRs with regard
to functions, processes, and values. The scientific
names of plants and animals used in the text
are provided in Appendix A. This information is
important as a baseline for understanding the impact
of past land alterations and for developing guidelines
for future management. In contrast, the section
on wildlife conservation is intended to provide
perspective regarding potential NWR contributions
to natural resources based on conservation plans
that have been developed for application at larger
geographic scales that encompass the NWR. The
section on evaluation of the wetland community
discusses in more detail the processes impacting
current wetland conditions. Included in this
discussion are terrestrial habitats within the
catchment because many biological features of
importance in wetlands (e.g., plants, invertebrates)
are impacted by processes (e.g., surface runoff,
water quality, erosion and deposition of sediment)
that originate in the uplands. The intent is to
provide thoughts regarding potential information
that will assist the USFWS in developing achievable
biological objectives during CCP development. The
recommendations are largely those of the authors
and are based on thoughts that resulted from
discussions with USFWS personnel during the
site visit. Further, the information needs identified
are known to be incomplete from a biological
perspective and largely ignore recreational and
other considerations. Thus, additional effort will
be required by USFWS personnel to identify and
integrate issues, concerns, and recommendations
through internal discussions and public scoping.
Description
Refuge Establishments and Authorities
All three NWRs considered in this report were
established under Executive Order and are
managed under authority of the National Wildlife
Refuge Administration Act and all other authorities
established by legislation pertaining to the NWRS.
Long Lake NWR (9025 ha) is managed as a separate
unit, whereas, Slade (1214 ha) and Florence Lake
(764 ha) NWRs are considered part of the Long
Lake Wetland Management District (WMD), a
three-county (Burleigh, Kidder, Emmons) area in
south-central North Dakota. In addition to Slade
and Florence Lake NWRs, the 69,580-ha WMD also
includes 80 waterfowl production areas ([WPA],
8711 ha), 1013 wetland easements (40,646 ha), six
easement NWRs (2342 ha), 43 grassland easements
(6556 ha), and one wildlife development area (WDA;
321 ha). The WDA was purchased and developed
by the Bureau of Reclamation and transferred to
the USFWS in 1991 for management as a mitigation
obligation of the Garrison Diversion Project (URL
http://longlake.fws.gov/Wmd.htm). The NWR
purposes are based on land acquisition documents
and authorities only (URL http://refugedata.fws.gov/
databases/purpose) and do not include purposes that
may be identified in other documents, including deed
restrictions, management agreements with primary
land managers, and congressional established
wilderness designations which were not part of the
acquisition documents and authorities.
Long Lake NWR. Established “... as a refuge and
breeding ground for migratory birds and other
wildlife ...” (Executive Order 8119, dated 10 May
1939), “... for use as an inviolate sanctuary, or for any
other management purpose, for migratory birds” (16
U.S.C. § 715d [Migratory Bird Conservation Act]),
and “... shall be administered by him [Secretary
of the Interior] directly or in accordance with
cooperative agreements ... and in accordance with
such rules and regulations for the conservation,
maintenance, and management of wildlife, resources
thereof, and its habitat thereon, ...” (16 U.S.C. § 664
[Fish and Wildlife Coordination Act]).
Slade NWR. Established “... for use as an inviolate
sanctuary, or for any other management purpose, for
migratory birds” (16 U.S.C. § 715d [Migratory Bird
Conservation Act]).
Florence Lake NWR. Established “... as a refuge
and breeding ground for migratory birds and other
wildlife ...” (Executive Order 8119, dated 10 May
1939), “... for use as an inviolate sanctuary, or for any
other management purpose, for migratory birds.”
(16 U.S.C. § 715d [Migratory Bird Conservation
Act]), and “... shall be administered by him
[Secretary of the Interior] directly or in accordance
with cooperative agreements ... and in accordance
with such rules and regulations for the conservation,
maintenance, and management of wildlife, resources
thereof, and its habitat thereon, ...” (16 U.S.C. § 664
[Fish and Wildlife Coordination Act]).
Location and Formation
All three NWRs are located in south-central
North Dakota: Long Lake NWR in Burleigh and
Kidder Counties, Slade NWR in Kidder County,
and Florence Lake NWR in Burleigh County
(Figure 1). This area is part of the Interior Plains
major physiographic division, the Great Plains
province, and the Glaciated Missouri Plateau section
(Fenneman 1931).
Preglacial drainage of the area included the
ancestral river systems of the Knife, Cannonball,
Heart, and Grand Rivers that trended northeast
and flowed into Hudson Bay (Kume and Hansen
1965). The ancient Cannonball River may have been
a tributary to the ancestral Red River (Lemke and
Colton 1958). At this time, the Missouri River flowed
northeast from the northwest corner of North
Dakota to Hudson Bay (Flint 1955).
During the Wisconsin Stage of the Pleistocene, ice
advanced four and at least three times in Burleigh
and Kidder counties, respectively (Rau et al. 1962,
Kume and Hansen 1965). The Napoleon ice sheet
(Burleigh County only) advanced first, followed by
the Long Lake, Burnstad, and Streeter advances
in both counties. Each ice advance was halted by
buttes and mesas that comprise the eastern border
of the Missouri Couteau in central North Dakota
and was followed by a period of stagnation and
melting (Rau et al. 1962). For example, the Napoleon
advance was followed by a period of glacial retreat
and erosion that may have lasted more than 25,000
years (Clayton 1962). This activity resulted in the
deposition of dead-ice moraine (i.e., landforms
composed of hummocky accumulations that are
primarily till deposited by glacial ice) behind the end
moraines and generated large amounts of outwash
(e.g., glaciolacustrine and glaciofluvial sediments) in
front of the terminal end point of each advance (Rau
et al. 1962). In addition, the ancestral Missouri River
was blocked and diverted to the southeast.
A Preliminary Biological Assessment of Long Lake National Wildlife Refuge Complex, North Dakota
The Long Lake advance occurred about 12,000 to
13,000 years ago and deposited end and ground
moraine in the eastern and western portions of
Burleigh and Kidder counties, respectively. At this
time, the valley currently occupied by Long Lake
NWR constituted part of the Cannonball River. The
preglacial valley was > 1.6 km wide and ranged
from 30 to 91 m in depth (Rau et al. 1962). The initial
lobes of the Long Lake advance followed bedrock
lows and a lobe of ice pushed along the valley of the
Cannonball River south of Steele and deposited a
great loop of end moraine in the vicinity of Long
Lake (Rau et al. 1962). As this glacier retreated,
ground moraine was deposited and meltwater flowed
through preexisting channels (stream flow was to
the south rather than the preglacial direction of
northeast) to newly formed glacial lakes McKenzie
and Steele (Rau et al. 1962, Kume and Hansen 1965).
As further melting occurred, dead-ice moraine was
deposited on bedrock highs adjacent to main valleys
and the valleys were filled with outwash and ponded
sediment because meltwater was confined behind
the end moraines that dammed the ancestral rivers
(Rau et al. 1962, Kume and Hansen 1965, Bluemle
2000).
About 12,000 years ago, the Burnstad glacier
advanced and overrode the Long Lake end moraine
in the northern part of Burleigh County and
southeastern Kidder County. The margin of the
Burnstad glacier stagnated and formed dead-ice
moraine. Meltwater transporting outwash from
this glacier flowed through Apple Creek, Random
Creek, and the Cannonball River channels into
Glacial Lake McKenzie and formed an outwash
plain in the northern portion of the lake. Cutting
and filling on the floodplain of the Missouri River
perhaps formed the higher terraces at this time.
Finally, the Streeter ice sheet advanced into
northern Burleigh and eastern Kidder counties and
deposited a number of end moraine loops along its
leading edge. As this glacier retreated, a large sheet
of outwash was deposited on the older drift from
Robinson to Lake George and filled major bedrock
valleys with stratified drift (Rau et al. 1962). This
outwash collapsed as ice from the Burnstad glacier
melted and collapsed. As melting of the Burnstad
ice continued, which may have occurred for more
than 2,000 years (Clayton 1962), the resulting
deposits of dead-ice moraine slowly assumed their
present topography. In addition, the amount of
meltwater was sufficient to eventually breach the
Long Lake end moraine and thereby allow transport
of sediment-laden waters to the Missouri River and
Glacial Lake McKenzie (Kume and Hansen 1965).
During the Recent Age (5000 years ago to present),
the area has been modified by stream erosion
and slope wash to establish the present drainage
pattern that consists of the Missouri River and its
tributaries. The present channel of the Missouri
River comprises segments representing preexisting
river channels and segments of superposed
drainage divide channels. The diverted Missouri
River channel captures many east flowing rivers
on the Missouri Plateau section, but the tributary
pattern is asymmetrical with well developed western
tributaries (e.g., Knife, Heart, and Cannonball
rivers) and underdeveloped eastern tributaries
(Snake, Painted Woods, Burnt, Apple, and Badger
creeks). In southern Burleigh and Kidder counties,
streams drain into the Long Lake trough, which also
contains Lake Etta and Lake Isabel, whereas Lake
George and Alkali Lake receive discharge from the
surface streams in the southeast corner of Kidder
County. However, the majority of intermittent
streams that originate in the end, dead-ice, and
recessional moraines flow into small lakes and
sloughs or disappear by infiltration into outwash.
Landform and Topography
The Glaciated Plains section is comprised of several
subdivisions; however, the number and boundaries of
subdivisions vary depending on the source consulted
(Fennemen 1931, Clayton 1962, Lemke and Colton
1958, Kume and Hansen 1965). This report adheres
to the boundaries proposed by Kume and Hansen
(1965), which places Long Lake and Slade NWRs
in the Long Lake Basin subdistrict of the Coteau
Slope district and Florence Lake NWR in the
Missouri Coteau district. The Coteau Slope district
is characterized by streams that are predominantly
intermittent or ephemeral and drainage that is
internal and partially integrated. The area is
subject to active erosion by integrated streams that
discharge to the Missouri River (Kume and Hansen
1965). Drift in this area is largely from the early
Wisconsin and thickness ranges from moderate to
nonexistent (Clayton 1962). More specifically, the
Long Lake Basin subdistrict largely is composed
of outwash and lake plain. Ground moraine flanks
outwash on the north and south sides of Long Lake.
The till (i.e., generally fine-grained, unstratified, and
unsorted material of various types that ranges in
size from clays to boulders) of this moraine is sandy
and pebbly, and exhibits a low undulating surface
that extends from the outwash plain adjacent to
Long Lake toward the end moraine at higher
elevations (Kume and Hansen 1965).
Long Lake NWR, as well as Lake Etta and Lake
Isabel, is situated in the partially buried valley of the
ancestral Cannonball River. The depth to bedrock
in the main valley of the ancestral Cannonball River
between Long Lake and Lake Etta was 91 m and the
difference in elevation between the depth to bedrock
on the old upland surface at Steele, North Dakota,
and the floor of the Cannonball south of this location
was > 145 m prior to glaciation. Thus, the preglacial
surface exhibited considerable relief and must have
resembled the bluffs that flank the Missouri River
trench (Rau et al. 1962). In contrast, elevations in
the basin following glaciation range from about 549
m at the edge to about 518 m in the center (Kume
and Hansen 1965). Thickness of the valley fills
range from 38 to 51 m in Burleigh County to 91 m
in Kidder County. Surface deposits are mostly sand,
but clay deposits also are common.
The Missouri Coteau district, which encompasses
Florence Lake NWR, is characterized by non-integrated
drainage and numerous undrained
depressions. The few streams that exist in
the district are of short length, tend to exhibit
ephemeral flows, and typically drain into nearby
lakes and kettles. Drift largely is from the Late
Wisconsin and thickness of glacial till ranges from
a feather edge to 50 m (average = 18 m). The area
is dominated by extensive dead-ice moraine and
associated stagnant ice-disintegration features,
including numerous kettles, disintegration ridges
and trenches, and kames (Kume and Hansen
1965). The dead-ice moraine occurs at elevations
ranging from 661 to 640 m) and maximum relief is
about 30 m. Another glacial landform in the district
is collapsed outwash topography (i.e., landforms
composed of hummocky accumulations of stratified,
primarily glaciofluvial drift sediment), which
contains abundant kettles and other ice-contact
features. Embedded within the collapsed outwash
topography are numerous saline and fresh lakes,
including Florence Lake (Kume and Hansen 1965).
Topography has been influenced by glacial activity
that reduced the local bedrock relief by abrading
and reducing the elevation of higher bedrock areas
and differentially filling valleys with glacial drift.
The maximum relief in Kidder County is 152 m, but
local relief varies from 3 to 15 m. Elevations on the
collapsed outwash range between 561 and 579 m.
Soils
Information in this section represents a general
summary intended to outline general soil
characteristics.
The bedrock in Burleigh County consists of 2438 m
of Paleozoic, Mesozoic, and Cenozoic sedimentary
rocks. The Surface bedrock includes the Late
Cretaceous Pierre (marine shale), Fox Hills (marine
sandstone), and Hell Creek (sandstone, mudstone,
siltstone, lignite, carbonaceous shale) Formations,
and the Tertiary Paleocene Fort Union Group
consisting of the Ludlow (continental sandstone,
lignite, and shale), Cannonball (marine sandstone,
siltstone, shale, and limestone), and Tongue River
(continental sandstone, claystone, siltstone, shale,
limestone, and lignite) Formations (Kume and
Hansen 1965). Beneath the glacial drift in Kidder
County, the uppermost bedrock includes the Pierre
and Fox Hills Formations of the Late Cretaceous
and the Cannonball and Tongue River Formations of
the Fort Union Group (Rau et al. 1962).
The glacial till that overlies most of the surface
bedrock in Kidder and Burleigh counties is similar
with respect to physical characteristics. There are
no significant differences in size, and differences
in color and pebble composition are subtle (Rau
et al. 1962, Kume and Hansen 1965). Grain size
analyses of 47 samples from Kidder County
indicate the sand, silt, and clay percentages of till
range from about 1.0 – 58.5, 22.0 – 45.0, and 18.9
– 77.0, respectively. However, if two samples are
excluded, ranges of grain size are 24.0 – 58.5%
sand, 13.3 – 45.0% silt, and 18.9 – 46.8% clay,
respectively (Rau et al. 1962), which is similar to
the grain analyses of 34 till samples in Burleigh
County (18.0 – 50.4% sand, 23.8 – 41.6% silt, and
23.5 – 49.9% clay) (Kume and Hansen 1965). Most
of the till in Kidder County has reddish-yellow
spots caused by oxidation of iron oxide originating
from Pierre Shale, and a white mottling caused by
concentration of calcium carbonate (Rau et al. 1962).
In Burleigh County, oxidized till occurs to depths
of 6 to 9 m and exhibits a mottled appearance due
to calcium carbonate concentrations. In addition,
free pebbles are frequently encrusted with caliche
and particles of shale and lignite are common
(Kume and Hansen 1965). In contrast, glaciofluvial
sediments in both Kidder and Burleigh counties are
comprised primarily of stratified sands and gravel
that range in size from fine sand to pebbles, whereas
glaciolacustrine sediments primarily consist of silts
and clays.
The principal parent materials of soils on all three
NWRs are glacial till, glacial outwash, and sediments
of glaciolacustrine and glaciofluvial origin. The
physical and mineralogical properties of this parent
material, in combination with long-term climatic
regimes, have greatly influenced the physical and
chemical properties of soils. Taxonomically, soils
within the boundaries of the three NWRs belong to
more than 20 series (Table 1) and nine subgroups
(typic and pachic Argiborolls; typic, entic, pachic,
and udic Haploboralls; typic Ustipsamments; typic
Natraquolls; and typic Psammaquents) (Stout et
al. 1974, Seelig and Gulsvig 1988). These soil series
form 10 associations (i.e., areas with a proportional
pattern of soils that normally consist of one or
more major soils and at least one minor soil) that
comprise the terrestrial land base of these three
NWRs. Of these, the dominant associations on all
three NWRs are loams and sands derived from
glacial outwash and glacial till that typically are
deep, medium to moderately coarse in texture,
range in available water capacity from very low to
high, and are susceptible to erosion by either wind
or water (Stout et al. 1974, Seelig and Gulsvig 1988).
Soils underlying uplands on Long Lake NWR are
sands and clays, whereas most soils underlying
uplands on Slade NWR and Florence Lake NWR
are a sand-silt mix and sandy loam underlain by
gravel, respectively (URL http://longlake.fws.gov/).
With the exception of the Lehr-Wabek-Manning
(nearly level to steep) and Harriet-Minnewaukon-
Stirum (level) associations, all other soil associations
occur in areas topographically characterized as
nearly level to rolling or gently rolling. Within each
association, individual soil series typically can be
arranged based on slope position.
Wetland features do not occupy a large proportion
of the area considered at the scale of an association;
thus, soils underlying wetlands (e.g., depression,
basins, swales, shallow drainages) are not adequately
represented at the level of the soil association.
In addition, soil associations do not adequately
address the soils derived from glaciolacustrine
A Preliminary Biological Assessment of Long Lake National Wildlife Refuge Complex, North Dakota
and glaciofluvial sediments that underlay lakes
within the boundaries of the three NWRs (Stout
et al. 1974). Soils in these series often have unique
characteristics, including highly calcareous soils
(e.g., Arveson and Colvin series), dense alkali subsoil
(e.g., Noonan series) and the presence of claypans
(e.g., Belfield, Daglum, and Rhoades series). As a
result, soils underlying wetlands often exhibit very
different properties compared to the major soils
composing an association; thus, characteristics of
individual soil series must be evaluated (Table 2). In
general, soils in these series exhibit very slow to only
moderate permeability, moderate to high available
water capacity, moderate to high organic matter
content, and medium to high fertility.
Climate
The climate of North Dakota is continental
(Rosenberg 1987, Harrington and Harman 1995),
and is characterized by relatively short, moderately
hot summers and relatively long, cold winters
(Kantrud et al. 1989). Other general climatic
features of the state include large annual and daily
temperature fluctuations, light to moderate annual
precipitation that varies in time of occurrence,
low relative humidity, and nearly continuous air
movement (Jensen undated). This large variation
is due primarily to geographic location. The Rocky
Mountains act as a barrier to the prevailing westerly
flow of atmospheric air and modify Pacific Ocean
air masses from cool and moist to mild and dry. In
contrast, cold, dry air masses originating in northern
Polar Regions and warm, moist air masses from the
Gulf of Mexico easily overflow North Dakota because
mountain barriers are lacking. Thus, the climate of
the state is influenced by cold, dry air masses from
Polar Regions, warm, moist air masses from tropical
regions, and mild, dry air masses from the northern
Pacific (Lemke 1960). These air masses flow through
North Dakota during every season and typically
progress rapidly, which causes frequent and rapid
weather changes.
Climate information in this report was obtained
from weather station 326015 operated by the High
Plains Regional Climate Center (URL http://www.
hprcc.unl.edu/) located at Moffit, North Dakota.
Depending on the variables of interest, data for this
station are available from 1948 to 2004. The average
annual temperature is 6.1o C, but the average
annual minimum and maximum temperatures
range from -1.4o to 13.0o C. Based on long-term
monthly averages, January is the coldest month
(mean = -12.4o C), followed by February (-8.7o
C) and December (-8.7o C), whereas the warmest
months are June (18.6o C), July (21.4o C), and August
(21.0o C). Further, the annual average number of
days with maximum and minimum temperatures
of > 32.2o C and < 0o C, respectively, is 25 and 73.
However, differences between monthly average
minimum and maximum temperatures are as much
as 11 to 17o C. The growing season, defined as the
long-term average number of consecutive days that
the minimum temperature does not fall below 0o C,
ranges from 99 to 147, which correlates well with
an average frost-free period of 120 days reported
for central North Dakota (Winter et al. 1984). The
average dates of last spring and first fall frosts
in Kidder County are 24 May and 13 September,
respectively, and average frost penetration is about
1.2 m (Lemke 1960, Rau et al. 1962).
Average annual total precipitation is 40.6 cm, of
which 73% (30.2 cm) occurs primarily as rain from
May through September. In contrast, the average
annual lake evaporation ranges from 83.8 to 102.0
cm) (Shjeflo 1968, Kantrud et al. 1989). Thus, the
region exhibits a negative precipitation:evaporation
ratio and lands in Burleigh and Kidder counties are
considered semiarid (Rau et al. 1962, Kume and
Hansen 1965). The annual average number of days
with precipitation events that are > 0.03 cm and >
0.3 cm are 71 and 35, respectively. In summer, most
rainfall is associated with thunderstorms (average
= 25 to 35 days per year) (Shjeflo 1968). In most
years, at least some part of the state experiences a
severe storm that produces 5.1 to 7.6 cm of rain in
24 hrs, and occasionally 12.7 to 15.2 cm or more can
occur in one day (Jensen undated). At Moffit, the
largest single day precipitation event was 11.9 cm.
In contrast, average monthly precipitation during
winter is only 2.4 cm and occurs mostly as snow.
Despite the northerly location, average annual
statewide snowfall is only 63.5 - 114.3 cm, which is
less than other northern states.
Ground Water and Surface Water
Essentially all water in this region is derived
from precipitation; however, some portion of this
water enters the ground through direct or indirect
percolation or is transported along the ground
surface to topographically lower areas. For example,
many river and stream valleys function to collect
excess surface water that cannot be absorbed into
soils at local scales. In general, ground water is
abundant in both Burleigh and Kidder counties (Rau
et al. 1962, Kume and Hansen 1965). However, the
amount of ground-water recharge that occurs varies
locally and depends on numerous factors, including
topography, climatic variables (e.g., precipitation
and temperature patterns), and soil characteristics
(e.g., available water capacity). In general, ground-water
recharge tends to be greatest during periods
of major precipitation that result in large amounts
of surface runoff (Randich and Hatchett 1966).
Further, areas dominated by alluvium (e.g., many
wetland features) and glaciofluvial silts, sands, and
gravels (e.g., valleys or channels that historically
transported glacial melt-water runoff) are
permeable and capable of collecting, transmitting,
and storing water (alluvium = 189 liters per minute
[lpm], glaciofluvial sediment yields = 568 – 3785
lpm). In contrast, lacustrine deposits comprised
of sandy silts and clays can collect and store large
quantities of water, but are generally of limited
permeability and yield only small quantities of
water (Randich and Hatchett 1966). Therefore, the
largest aquifers are located in the sands and gravels
in the Missouri River terraces and buried drainage
channels, but smaller aquifers also exist in the
sandstones and sands of the Fox Hills, Hell Creek,
Cannonball, and Tongue River Formations (Randich
and Hatchett 1966).
The chemical quality of ground water varies among
aquifers and locally depending on numerous factors,
including the materials water contacts in the
atmosphere and soil, extent of bacterial activity, soil
properties (e.g., base exchange), and the physical
interaction of surface water with ground-water
flow systems (Randich and Hatchett 1966, Lissey
1971, Winter 1977, Swanson et al. 1988). Although
limited, available water quality data obtained from
wells (domestic and stock) within or near each of the
NWRs suggest differences occur within and among
sites with different geologic material (Table 3). For
example, the specific conductance of ground water
on Long Lake NWR ranged from 734 mmhos per
cm in glacial drift to 2496 mmhos per cm in Foxhills
sandstone, whereas concentrations of sulfate ranged
from 2.7 ppm in Foxhills sandstone to 131.0 ppm in
glacial outwash. Differences also exist within the
same material on Long Lake NWR. For example,
concentrations of sodium and bicarbonate in ground
water collected from glacial drift material ranged
from 33 to 246 ppm and 329 to 641 ppm, respectively
(Randich et al. 1962, Randich and Hatchett 1966,
Table 3).
In general, the chemistry of precipitation is
relatively free of contaminants. However, as excess
rainwater (i.e., above soil saturation) is transported
across the soil surface (i.e., runoff) it can accumulate
various materials (e.g., agrichemicals) prior to
discharging into a wetland basin. The concentration
of these constituents is further modified by
climate. For example, all three NWRs are located
in a climatic zone characterized by a negative
precipitation:evaporation ratio that concentrates
chemical constituents seasonally and intra-annually
due to evapotranspiration. Thus, the surface water
chemistry of wetlands tends to be dynamic because
of complex interactions among numerous factors,
including the position of the wetland in relation to
ground-water flow systems, chemical composition
of ground water, surrounding land uses, and
climate (LaBaugh et al. 1987, Swanson et al. 1988,
Winter 2003). Given the variability within and
among wetland basins, it is not possible to provide
a general characterization of surface water quality
for these three NWRs. However, water quality of all
three units of Long Lake NWR has been recorded
previously. In May of 1969, several water quality
parameters were collected at the following locations:
(1) on the east and west sides of a road crossing
Long Lake, (2) Upper Harker and Harker lakes on
Slade NWR, and (3) Lake Isabel that adjoins Slade
NWR on the west (Swanson et al. 1988). The pH of
water at both Long Lake locations was about 9.0,
total alkalinity (mg per L) was 480 (west) and 860
(east), specific conductance (μS per cm) was 1560
(west) and 4150 (east), and sulfate concentration (mg
per L) was 900 (west) and 1185 (east). In contrast,
the pH of water in lakes on Slade NWR ranged from
8.7 (Upper Harker) to 9.3 (Harker), total alkalinity
(mg per L) ranged from 950 (Upper Harker) to 1540
(Harker), specific conductance (μS per cm) ranged
from 2300 (Isabel) to 4700 (Harker), and sulfate
concentrations (mg per L) ranged from 350 (Isabel)
to 1050 (Harker). Although quantitative reports of
water quality were not located for Florence Lake
NWR, the values obtained illustrate the differences
that can occur among lakes within similar
physiographic areas (e.g., subdistricts, districts).
In addition, differences can occur within different
portions of the same basin. For example, in April
2004 the specific conductance (μS per cm) of water
in Long Lake NWR Unit 1, Unit 2, and Unit 3 was
1910, 2600, and 4200, respectively (RAG).
In March of 1989, another water quality study was
conducted on Long Lake NWR (Olson and Welsh
1991). Complete data from this report were not
located, but concentrations of certain elements
were provided. In general, the alkalinity and
nutrient concentrations of Long Lake surface
water were high, which is typical of prairie lakes in
this region; however, elevated mercury and boron
concentrations and high sodium concentrations
also were documented (Swanson et al. 1988). Given
the alkalinity of the lake, however, the observed
mercury concentrations in surface waters would not
be readily activated biologically.
Vegetation
Historically, the landscape of south-central North
Dakota was characterized by numerous wetlands
embedded in a background matrix of northern
mixed-grass prairie (Fennemen 1931). Distribution
and density of wetlands was correlated with various
glacial landforms in the region. The greatest area
of semipermanent palustrine wetlands occurred
in areas of dead-ice and terminal moraine (e.g.,
Missouri Coteau), whereas the greatest area of
temporary and seasonal wetlands occurred in the
ground moraine and lake plain (Kantrud et al. 1989).
In contrast, rivers and lakes occurred predominantly
in topographically low areas that transported
meltwater from retreating glaciers.
The composition of vegetation in wetlands changes
dynamically in response to numerous factors,
including short- and long-term hydroperiods and
water chemistry (Kantrud et al. 1989, Euliss et al.
2004). Most palustrine basins exhibit concentric
zones of vegetation that are dominated by different
plant species (Kantrud et al. 1989). The most
commonly used terms to refer to these zones are,
in decreasing order of water permanency, deep
marsh, shallow marsh, and wet meadow (Kantrud
et al. 1989). The water regime in a deep marsh zone
usually is semipermanent. Dominant plants include
cattail, bulrush, submersed or floating plants,
and submersed vascular plants, but this zone also
may be devoid of vegetation if bottom sediments
are unconsolidated. Shallow marsh zones usually
are dominated by emergent grasses, sedges, and
some forbs, but submersed or floating vascular
plants also may occur. Wet meadow zones also
are typically dominated by grasses, rushes, and
A Preliminary Biological Assessment of Long Lake National Wildlife Refuge Complex, North Dakota
sedges, but submersed or floating plants are absent.
The primary difference between these zones is
hydroperiod. Surface flooding of the shallow marsh
zone usually is seasonal and ranges from spring to
mid- or late summer. In contrast, inundation of the
wet meadow zone typically is only temporary (e.g.,
one to several weeks in spring or briefly after heavy
summer rains).
The gradient from fresh to hypersaline water
is a continuum, and any divisions are arbitrary
(Euliss et al. 2004). In addition, salinity levels can
fluctuate widely within and among seasons (Stewart
and Kantrud 1972). In general, however, surface
water in temporary and seasonal wetland basins is
usually fresh (< 500 micromhos per cm) or slightly
brackish (500 - 2000 micromhos per cm), whereas
semipermanently flooded basins are often brackish
(5000 – 15,000 micromhos per cm), but can range
from fresh to subsaline (1500 0- 45,000 micromhos
per cm) (Stewart and Kantrud 1971). Although the
general effect of increased salinity in any zone of
wetland vegetation is a decrease in species diversity,
it is difficult to establish meaningful salinity
tolerances for individual species in their natural
habitats because of the complex interaction of abiotic
factors. However, general estimates of salinity
tolerance are available for numerous emergent and
aquatic plant species (Kantrud et al. 1989).
Uplands historically were comprised of warm-season
grasses characteristic of both the short-grass
prairie and the cool- and warm-season grasses
characteristic of the tall-grass prairie (Samson
et al. 1998); thus, the area represented a zone of
ecotonal mixing that included a diversity of short,
intermediate, and tall grass species (Bragg and
Steuter 1996). Vegetation composition at regional
and local scales was determined by numerous
interrelated factors, including elevation, topography,
climate, soil characteristics, herbivory, and fire
(Hanson and Whitman 1938, Coupland 1950, URL
http://www.worldwildlife.org/wildworld/profiles/
terrestrial/na/na0810_full.html). The mixed-grass
prairie in North Dakota has been classified into nine
major vegetation types based primarily on plant
species composition and topography (Hanson and
Whitman 1938). Species typical of all these types
include western wheatgrass, blue grama, prairie
junegrass, needle-and-thread, Sandberg’s bluegrass,
little bluestem, needleleaf sedge, and threadleaf
sedge (Whitman 1941, Kantrud and Kologiski 1982).
However, even within a vegetation type, local
variation exists. For example, in xeric areas the
blue grama, needle-and-thread, and threadleaf
sedge association also included western wheatgrass,
prairie junegrass, and needleleaf sedge as less
important dominant grasses and about 12 dominant
forbs (e.g., lotus milkvetch, narrowleaf goosefoot,
scarlet beeblossom, flatspine stickseed, stiffstem
flax, spiny phlox, woolly plantain) (Hanson and
Whitman 1938, Coupland 1992). In contrast, more
mesic areas in the same association supported more
slender wheatgrass, fendler threeawn, sideoats
grama, little bluestem, porcupine grass, green
needlegrass, and sun sedge, whereas dominant
forbs included tarragon, prairie sagewort, white
sagebrush, blacksamson echinacea, and white
milkwort (Sarvis 1920). Other associations include
those on sandy loams and fine sandy loams that
typically occurred on topographically high areas, as
well as those that tended to occur in depressional
areas dominated by silt loams and silty clay loams
characterized by increased soil moisture and high
concentrations of carbonates and soluble salts. The
former were dominated by grasses in the Bouteloua
(grama) and Stipa (needle-and-thread, green needle,
porcupine) genera, and sedges in the Carex genus,
whereas the latter were characterized by species
such as inland saltgrass, Nuttall’s alkaligrass, and
foxtail barley (Hanson and Whitman 1938).
Human alteration (e.g., conversion to agricultural
production) of the landscape has resulted in the loss
of > 50% of wetlands (Dahl 1990) and 68% of mixed-grass
prairie in North Dakota (Samson et al. 1998).
The current total wetland area is 38,342 and 52,831
ha, respectively, in Burleigh and Kidder counties
(Reynolds et al. 1997, Table 4). Semipermanent
wetlands (11,952 ha) and lakes (24,313 ha) constitute
the greatest wetland area in Burleigh and Kidder
counties, respectively; however, seasonal wetlands
occur in the highest density in both counties
(Burleigh County = 6.16 per km2, Kidder County
= 6.66 per km2) (Reynolds et al. 1997). Further,
approximately 68% of the land in the counties
(Burleigh, Kidder, and Emmons) that comprise
all three NWRs and the WMD remains in native
grassland (URL http://mountain-prairie.fws.gov/
reference/briefing_book_nd_2000.pdf). However,
in addition to habitat loss and fragmentation, the
ecological processes determining the structure and
function of remaining native communities also have
been severely impacted. For example, the World
Wildlife Organization considers the mixed-grass
prairie among the most disturbed of all grassland
ecoregions; only a few remnant patches remain
and none are considered intact (URL http://www.
worldwildlife.org/wildworld/profiles/terrestrial/
na/na0810_full.html). Major perturbations include
altered hydrology (e.g., ground water withdrawal,
construction of dams), the use of pesticides (e.g.,
in 1991 more than 100,000 metric tons applied in
the mid-continent; Samson et al. 1998), cessation
or alteration of historic burning regimes, modified
animal communities, and introduction of exotic
plants.
The above impacts are evident on portions of each
NWR considered in this report. Most lakes and
wetlands occurring on Long Lake NWR are located
in and along the distal side of morainal areas that
exhibit nonintegrated drainage. Water in these
areas is collected locally and dissipates primarily by
evapotranspiration and percolation into the water
table. However, following purchase by the USFWS
in the 1930s, the Civilian Conservation Corps (CCC)
constructed three dikes to control water levels in
Long Lake, built several small dams across ravines
that discharged water to Long Lake for the purpose
of ponding water in additional areas, and constructed
19 duck nesting islands in Units 1 and 2 of Long
Lake (URL http://longlake.fws.gov/History.HTM).
Many upland areas purchased as part of Long Lake
NWR previously had been cultivated under private
ownership. After acquisition by the USFWS, some
of these lands continued to be cultivated, some were
planted with tame grass mixes, and most continued
to be invaded by noxious exotic plants (e.g., Canada
thistle, absinth wormwood).
The current composition of wetlands on Long Lake
NWR (total = 7096 ha), based on National Wetland
Inventory (NWI) data provided by Complex staff,
includes lakes (6558 ha), semipermanent wetlands
(187 ha), seasonal wetlands (25 ha), temporary
wetlands (116 ha), and riverine habitat (6 ha, Table
5). In addition, Complex staff completed a habitat
inventory in 2003 that recorded 34 wetlands (11.2
ha) not classified by NWI. Long Lake, a 6071-ha
alkaline basin, is the predominant wetland on Long
Lake NWR. The remaining wetland area consists
of Long Lake Creek (riverine), natural wetlands,
dugouts, and man-made impoundments. Water-level
management is the primary strategy used to
manipulate wetland conditions on Long Lake and
adjacent marshes, but control often is limited. For
example, in some years water can be transported
to Unit 2 Marsh via gravity flow or pumping, but
dewatering can only occur by evapotranspiration.
The vegetation composition of wetlands on Long
Lake NWR is dynamic as evidenced by past reports
and observations of Complex staff. For example,
the presence of single-celled green algae, blue-green
algae, and phytoplankton (diatoms and
cyanobacteria) have been reported previously
(Metcalf 1931, Olson and Welsh 1991) and a plant
survey conducted in 1917 indicated that abundant
emergent plant species in Long Lake included
cosmopolitan bulrush, tule bulrush, and three-square
bulrush. This survey also reported common
spikerush as common, seaside arrowgrass, prairie
cordgrass, and common bladderwort as fairly
common, and softstem bulrush as rare (Metcalf
1931). In addition, aerial photographs of Long Lake
indicate dense stands of emergent growth, including
many species mentioned in the 1917 survey, have
been present in the units during past years (GAK).
During the site visit, algae were evident in the Long
Lake units but emergent and submergent vegetation
along the perimeter was minimal at the few locations
examined. Emergent vegetation in Unit 2 Marsh
included bulrush, cattail, common reed, prairie
cordgrass, saltgrass, seepweed, kochia, dock, and
cocklebur. However, a sufficient number of sites
were not visited to adequately characterize the
current composition or extent of wetland vegetation
and, unfortunately, the Complex staff does not have
an established monitoring program that would allow
an objective examination of vegetation dynamics in
wetlands.
Uplands (total = 1924 ha) on Long Lake NWR are
dominated (> 50% cover) by grasses (1531 ha),
noxious weeds (56 ha), shrubs (161 ha), trees (19
ha), and crops (142 ha, Table 5). Of the grassland
area, about 1416 ha consist of areas dominated
by non-native grasses, whereas introduced cool-season
grasses and legumes (i.e., dense nesting
cover [DNC]) occupies 72 ha). In contrast, the
area dominated by natives is only 11 ha and is
highly fragmented (n = 42 patches) (Table 5).
Areas dominated by noxious or invasive weeds
other than non-native grasses occur primarily
as scattered, small patches. Principal non-grass
noxious or invasive weed species are Canada thistle
(30 ha) and absinth wormwood (26 ha), with lesser
amounts of Russian olive and leafy spurge. Much
of the historic cropland on Long Lake NWR has
been seeded to native grass mixtures, tame grass,
or DNC; however, about 142 ha are still cultivated
(small grains = 133 ha, row crops = 9 ha) as part of a
seedbed preparation strategy for eventual reseeding
to native grasses. For example, approximately 73 ha
of farm fields were seeded to native grasses in 2002.
Other techniques used to manipulate the species
composition and structure of existing herbaceous
upland vegetation (native and non-native) includes a
combination of haying, grazing, prescribed burning,
and, in areas dominated by noxious or invasive plant
species, chemical and biocontrol agents.
In addition to the general vegetation characteristics
mentioned above, more detailed information on
upland plant species composition is available for six
priority management units on Long Lake NWR.
Permanent belt transects (25-m length) were
established in these units using a stratified-random
approach and methods (Grant et al. 2004). Strata
consisted of three site types (i.e., xeric, northeast
slopes, southwest slopes) and, within each unit-strata
combination, one transect was established
per 4 ha. One of these management units (G-6) was
seeded to a mix of cool and warm season native
grasses in June 2002; however, only 79% of this
74 ha unit was actually seeded. Based on 900 data
points (n = 18 belt transects) collected in 2004, the
frequency that native and exotic vegetation occurred
along transects was 36.2% and 63.8%, respectively.
These data also indicate that 6.4% and 59.7% of
G-6 currently is moderately and heavily invaded
by exotic plants, respectively (Table 6). The other
five units are comprised of virgin sod with a similar
land use history; thus, data for these units were
combined. In 2004, the frequency of native and
exotic vegetation occurrence along 74 belt transects
(n = 3700 points) in these five units was 19.8% and
80.2%, respectively. Further, these data indicate that
22.98% and 61.94% of these units are moderately and
heavily invaded by exotic plants, respectively (Table
6).
Prior to USFWS ownership, the land that now
comprises Slade NWR was purchased by Mr. Slade
in the mid-1920s for a private shooting club. During
the drought period of the 1930s, the land was tilled
to provide wildlife food, a large well (60,567 L per
10 A Preliminary Biological Assessment of Long Lake National Wildlife Refuge Complex, North Dakota
hr) was dug between Harker and Upper Harker
lakes, and a system of pipes and flumes was used
to transport water to the lakes. In addition, large
quantities of grain were purchased and shipped to
the area to provide supplemental food for waterfowl.
Currently, wetlands on Slade NWR are comprised
of five semipermanent wetlands, 15 temporary or
seasonal wetlands, and several manmade wetlands
(e.g., dugouts). Total wetland area is about 395
ha, with lakes and marshes predominating. Trees
occupy the margin of some wetlands and dead
widgeon grass was evident along the shoreline of at
least one lake. Other emergent vegetation recorded
in seasonal wetlands during the site visit included
smartweed, sedges, reed canary grass, and common
reed. Additionally, 26 aquatic and semiaquatic
plant species were identified during a 1968 survey,
including four species of bulrush, six species of rush,
narrow-leaved cattail, sprangletop, muskgrass,
American milfoil, common bladderwort, and sago
pondweed (GAK). There is evidence that the
temporary and seasonal wetlands had been farmed
prior to NWR establishment.
The balance of land (820 ha) comprising Slade NWR
is terrestrial and includes native grassland (81
ha), tame grass (522 ha), shelterbelts (16 ha), and
agricultural units (197 ha) (URL http://longlake.
fws.gov/Slade.HTM). The dominant tame grasses
are smooth brome and Kentucky bluegrass, and the
dominant noxious weed is leafy spurge. The majority
of farming on the NWR is organic. Terrestrial
lands periodically are hayed and grazed, and areas
dominated by leafy spurge are treated with a
combination of chemicals, biocontrol (e.g., beetles),
and haying.
Florence Lake NWR includes 594 ha of fee title and
170 ha of easement land (URL http://longlake.fws.
gov/FlorenceLake.HTM). Collectively, all or portions
of 78 wetland basins occupy 108 ha of this land base.
Based on NWI data, these basins are classified as
lakes (n = 4), semipermanent wetlands (n = 7),
seasonal wetlands (n = 56), and temporary wetlands
(n = 11). However, aerial photography indicates that
numerous smaller depressions were not mapped
(GAK). Based on a historic survey conducted in
1917, common spikerush and tule bulrush were
common in Florence Lake and sago pondweed and
spike watermilfoil were abundant (Metcalf 1931).
A current survey has not been conducted, but
scattered small patches of bulrush were noted along
the perimeter of some lakes, whereas spikerush,
smartweed, and pondweed were noted in a small
seasonal wetland during April 2004 (MKL).
The remainder of Florence Lake NWR consists of
native (395 ha) and tame (82 ha) grass, woodland
(6 ha), and crops (127 ha). Although approximately
82% of grasslands are often referred to as native,
baseline vegetation monitoring indicate current
species composition has been compromised to
varying extents (Table 6). Sampling methodology
was consistent with that of the belt transect data
collected on Long Lake NWR in 2004 (Grant et al.
2004). Based on 50 belt transects (n = 2500 data
points) established at varying locations on Florence
NWR, the frequency of native and exotic vegetation
occurrence along transects in 2002 was 7.0% and
93.0%, respectively. Further, these data indicate that
39.4% and 57.2% of the prairie has been moderately
and heavily invaded by exotic plants, respectively
(Table 6). Finally, farming has occurred periodically
on Florence NWR since the early 1960s, but crop
yields in recent years have been marginal. Thus,
the cooperative farming agreement on 45 ha of fee
title land was not renewed when it expired and these
areas were seeded to grass in 2000. The current 127
ha of crops occur only on easements that are not
controlled by the USFWS.
Wildlife Conservation
The primary purpose of NWR lands considered in
this report is as a breeding ground for migratory
birds and other wildlife; thus, any discussion
regarding management in relation to long-term
sustainability must be placed in this context. In
addition, the 1997 NWRSIA mandates that each
NWR develop a CCP consistent with the principles
of sound fish and wildlife management and available
science (Public Law 10557). The NWRSIA specifies
that each CCP shall identify and describe the
purposes of each NWR; the distribution, migration
patterns, and abundance of fish, wildlife, and
plant populations and related habitats; significant
problems that may adversely affect the populations
and habitats of fish, wildlife, and plants and the
actions necessary to correct or mitigate such
problems; and, to the maximum extent practicable
and consistent with the NWRSIA, be consistent
with fish and wildlife conservation plans of the state
in which each NWR is located. Although important,
the purpose of this report is not to fully develop
information on all species potentially occurring
on all three NWRs. However, some general
future direction must be specified with regard to
wildlife given the purpose for establishment of
each NWR. Therefore, this report concentrates on
the importance of all three NWRs for migratory
birds because they represent a primary USFWS
responsibility under requirements of the Migratory
Bird Treaty Act of 1918 (16 U.S.C. § 715d). However,
this focus should not be interpreted as meaning
other vertebrates, invertebrates, and plants can
be ignored because they are critical to proper
system function. In addition to various metrics of
biodiversity, lands of each NWR also contribute to
other ecosystem services at various spatial scales,
including floodwater storage, erosion control, and
water quality. Thus, information regarding other
natural resource values provided by each NWR
also should be developed and integrated prior to
evaluating the direction of future management.
Baseline information on the avian community of each
NWR considered in this report was developed using
a variety of data, including the 2002 version of the
Long Lake NWR Bird List, which is periodically
updated by Complex staff (URL http://longlake.
fws.gov/birdlist.HTM). Naming conventions for all
11
birds follows the American Ornithologists’ Union
Committee on Classification and Nomenclature
(American Ornithologists’ Union 1998, 2000, 2002,
2003). Several qualifying factors must be considered
when considering this species list. First, the 26
accidental species documented on Long Lake
NWR are not considered in this report. Second,
the list is based on bird sightings over a long
time period and it may not accurately represent
the current avian community. Third, the list only
reflects occurrence; thus, species populations on
each NWR are not known. Regardless of these
constraints, a list of avian species known to occur on
at least one of the NWRs considered in this report
can help focus discussion among individuals (e.g.,
USFWS personnel, core CCP team) responsible for
determining the future management direction.
The NWRSIA states that national and regional
plans must be consulted in developing a CCP. To
provide overall perspective, relevant information
regarding avian species of concern and population
targets contained in a representative sample of
these plans has been summarized (Appendix B),
but no attempt has been made to prioritize or make
decisions regarding species or guilds that should
receive attention. In some cases, species considered
to be of conservation concern at a regional level may
not be of concern at a national level, or vice versa.
Such differences do not indicate discrepancies;
rather, they suggest differences in distribution
and population status at different geographical
scales. Also, some species mentioned in regional
and national plans may not be incorporated in
the table even though one or more of these three
NWRs may potentially provide valuable resources
for those species. The relatively small size of each
NWR considered in this report precludes providing
quality habitat for all species and decisions likely will
be required to evaluate tradeoffs in management
approaches and for development of detailed habitat
objectives.
Long Lake NWR Complex. The importance of
NWR lands (including the WMD) for waterbirds was
a prime impetus for originally acquiring lands in fee
title and also for subsequent expansion of the land
base via fee title and easement acquisitions. Since
1987, the USFWS has conducted annual population
surveys of 13 waterfowl species in each of 15 WMDs
throughout the Dakotas and northeastern Montana.
Information derived from this survey includes
number of recruits, recruitment rates (i.e., the
number of young females fledged per adult female
in the breeding population), number of breeding
pairs, number of wet ponds, and wet area. Of the
13 primary duck species breeding in the Prairie
Pothole Region, the number of breeding pairs that
used lands comprising the Long Lake Complex
and surrounding private lands within the WMD
ranged from 8865 in 1990 to 544,017 in 1997, whereas
recruitment rates ranged from 0.40 in 1990 to 0.82
in 1997 (Table 7). According to the USFWS (1996),
a minimum recruitment rate of 0.49 is needed to
maintain a duck species’ population. Additionally,
positive relationships between wetland condition
(i.e., wet area, number of wet ponds) and both
breeding pairs and duck recruitment can be seen
throughout the 18-year survey period.
Information on nesting waterfowl is available from
upland fields on six WPAs (156 ha) in the Long
Lake WMD that were evaluated in 2001 and seven
management units (168 ha) on Long Lake NWR
evaluated in 2002 (GAK). Only fields dominated by
perennial cover and supporting > 31 duck pairs
per km2 were selected for study on WPAs, whereas
sites on Long Lake NWR were randomly selected.
Vegetation composition of fields evaluated ranged
from planted dense nesting cover, tame grass fields,
and native grassland on WPAs to exotic cool season
grass (e.g., Kentucky bluegrass, smooth brome) on
Long Lake NWR. Nest density on WPA fields was
approximately 0.76 per ha and Mayfield (Mayfield
1961) nest success (n = 110) of all species (n =
7) and study fields combined was 26.8%, which
is greater than the 15.0% nest success generally
accepted as the minimum for duck population
stability in this region (Cowardin et al. 1985, Klett
et al. 1988). However, Mayfield (Mayfield 1961)
nest success of individual fields ranged from 4.2% to
38.8% (Table 8). Nest density on Long Lake NWR
management units was approximately 1 per 2 ha and
Mayfield (Mayfield 1961) nest success (n = 79) of all
species (n = 6) and fields combined was only 3.0%
(range among individual study fields = 0.4 to 17.8%;
Table 8). The predominant nest predator on both the
WPA fields and Long Lake NWR management units
evaluated was the striped skunk; however nests also
were predated by badger, raccoon, and red fox.
Excluding accidental species, the 2002 Long Lake
NWR Bird List indicates that 278 species have been
recorded on Long Lake NWR or private land in
close proximity to the NWR, of which 129 have been
documented as nesting. This diversity of bird life
has resulted in national recognition of both Kidder
County and Long Lake NWR as two of the top 10
birding “hot spots” in the nation (Konrad 1996).
Long Lake NWR also is recognized as a Globally
Important Bird Area (IBA) (URL http://www.
abcbirds.org/iba/). The IBA program, initiated by
BirdLife International in Europe in the mid-1980s,
was developed to recognize and support sites of
importance to birds (Kushlan et al. 2002).
Long Lake NWR was designated as a regional
shorebird site in the Western Hemisphere Shorebird
Reserve Network (WHSRN) in 2002 because more
than 20,000 shorebirds use this NWR annually as
either a migratory stopover or breeding area (URL
http://www.manomet.org/WHSRN). From 2001 to
2004, shorebird surveys have been conducted on
Long Lake NWR following Manomet Center for
Conservation Sciences’ International Shorebird
Survey protocol. Although two survey routes have
been established, most surveys have been conducted
on the west route (comprised of the western 33% of
Long Lake NWR). From 2001 - 2003, 28 shorebird
species were recorded annually on Long Lake NWR,
12 A Preliminary Biological Assessment of Long Lake National Wildlife Refuge Complex, North Dakota
compared to 29 species in 2004. During this period,
the most abundant spring migrants include Wilson’s
Phalarope and Marbled Godwit, whereas the most
abundant fall migrants included Wilson’s Phalarope,
Long-billed and Short-billed dowitchers, American
Avocets, and Killdeer. Both shorebird abundance
and diversity has varied seasonally and annually
throughout the survey period; abundance has
ranged from 17,685 in spring 2004 to 1551 in spring
2003, whereas Simpson’s Diversity Index (Simpson
1949) (range = 0.0 [low] to 1.0 [high]) values have
varied from a seasonal low of 0.4978 to an annual
high of 0.8218 (GAK). The substantial variation in
shorebird abundance likely is related to wetland
conditions at scales greater than Long Lake NWR.
During years when numerous prairie wetlands are
flooded and the water level in Long Lake is high
(i.e., spring 2003), relatively few shorebirds use
Long Lake NWR. Conversely, substantially more
shorebirds use Long Lake NWR during years of
minimal spring runoff (i.e., spring 2004) because the
surrounding landscape is mostly dry and Long Lake
provides suitable shorebird habitat.
Also during 2002, wetlands within the boundaries
of Long Lake NWR and 10 WPAs (eight Bureau of
Land Management transfer tracts) were designated
as critical habitat for the federally threatened
Piping Plover by the USFWS, Division of Ecological
Services. Three fee title sites (Rath WPA, Rachel
Hoff WPA, and Long Lake NWR) designated as
Piping Plover critical habitat have been surveyed
at five-year intervals, beginning in 1991, as part of
the International Piping Plover Breeding Census
(GAK). This is a complete census intended to
provide moderate- and long-term information
necessary to assess the success of Piping Plover
recovery efforts and objectives (Ferland and Haig
2002). During the three survey years, 13 adults (six
on Rachel Hoff WPA and seven on Long Lake NWR)
were detected in 1991, five adults were detected on
Rachel Hoff WPA in 1996, and seven adults (two on
Rachel Hoff WPA and five on Long Lake NWR) and
three young (all on Rachel Hoff WPA) were detected
in 2001 (GAK).
The importance of the Long Lake NWR Complex to
colonial nesting waterbirds has been investigated.
In 2003, an aerial survey of all wetland basins (n =
864) on fee title lands within the Long Lake NWR
Complex was completed and each wetland was
assigned to one of three categories (high probability
[HPC], moderate probability [MPC], and low
probability [LPC]) based on the likelihood that the
basin would support one or more waterbird colonies
that year. Category assignments were based on
a combination of habitat conditions, including (1)
wetland cover type (Stewart and Kantrud 1971),
(2) hydrologic regime and basin size (based on NWI
data), and (3) special features (e.g., islands, dead
trees in wetland). All of the HPC wetlands (n =
68) were ground surveyed for waterbird colonies,
whereas 50% of the MPC wetlands (n = 83) and 5%
of the LPC wetlands (n = 32) were ground surveyed.
When a waterbird colony was located, species
composition was determined, nests were tallied, the
perimeter of the colony was delineated using a global
positioning system, and general habitat variables
were measured.
Forty colonies were located during the survey,
including 31 (77.5%) marsh colonies, eight (20%)
ground or island colonies, and one (2.5%) tree or
shrub colony. Twenty-four (60.0%) of the forty
colonies consisted of only one species, 11 (27.5%)
contained two species, three (7.5%) contained three
species, one (2.5%) contained five species, and one
(2.5%) contained eight species. Fourteen different
breeding waterbird species were recorded, but only
the Double-crested Cormorant utilized multiple
colony types. The number of breeding pairs of
each species detected during the survey ranged
from three pairs of Snowy Egret to 310 pairs of
California Gull (Table 9). Thirty-eight colonies
(95%) were located on HPC wetlands, whereas only
two (5%) colonies were located on MPC wetlands
and no colonies were located on LPC wetlands
(Table 9). The apparent success of the wetland
stratification scheme provided a colonial nesting
waterbird population estimate for NWR lands that
had low variance and provided an accurate estimate
of colonial nesting waterbird use of fee title lands
during the 2003 breeding season.
Finally, the Complex staff has monitored the relative
abundance and species composition of grassland/
wetland edge nesting passerines on Long Lake
NWR at 50 randomly selected 100-m radius points
annually from 2001 to 2004. Relative abundance
(mean number of breeding pairs per point),
estimated mean pairs per 100 ha, and frequency
of occurrence (percentage of total points at which
a species was detected) were calculated for all
detected species (Table 10). The number of species
detected annually ranged from 10 in 2002 to 14 in
2004 and the number of breeding pairs ranged from
258 in 2003 to 378 in 2004.
Bird Conservation Region. Lands of the Long
Lake NWR Complex are in the Prairie Pothole Bird
Conservation Region (BCR 11), an ecologically
distinct region of 715,000 km2 with similar bird
communities, habitats, and resource management
issues (North American Bird Conservation
Initiative, URL http://www.nabci-us.org/map.
html). The Prairie Pothole BCR comprises the core
breeding range of most dabbling duck and several
diving duck species, as well as provides critical
breeding and migration habitat for > 200 other
bird species. There are 29 species of conservation
concern listed for BCR 11 (USFWS 2002), all of
which have been recorded as occurring on Long
Lake NWR (Appendix B). Priority wetland species
that breed in the area include Yellow Rail, Piping
Plover, American Avocet, Marbled Godwit, Wilson’s
Phalarope, and Franklin’s Gull. In addition, wetland
areas in the region also provide important migration
habitat for the American Golden-Plover, Hudsonian
Godwit, White-rumped, and Buff-breasted
sandpipers. Priority species that breed in terrestrial
13
habitats include Sprague’s Pipit, Baird’s Sparrow,
and Chestnut-collared Longspur (USFWS 2002).
Birds of Conservation Concern. The Birds of
Conservation Concern (BCC) is the most recent
effort to satisfy the 1988 amendment to the Fish
and Wildlife Conservation Act, which mandates
the USFWS to “…identify species, subspecies, and
populations of all migratory nongame birds that,
without additional conservation actions, are likely to
become candidates for listing under the Endangered
Species Act of 1973” (USFWS 2002). The document
provides species lists at three geographic scales:
national, USFWS regions, and BCRs. Species
considered for inclusion include nongame birds,
game birds without hunting seasons, and numerous
categories (candidate, proposed endangered or
threatened, and recently delisted) used in the
Endangered Species Act. Parameters considered
in determining if species within these categories
are of concern include population size, extent of
range, threats to habitat, and other factors. The
BCC should be consulted for details regarding the
assessment process (USFWS 2002).
Of the 278 bird species on the Long Lake NWR
Complex Bird List, 49 are included in the BCC
(Appendix B). Of these, 23 species are of concern
at all three scales (i.e., BCR 11, Region 6 of the
USFWS, National), three species (Prairie Falcon,
American Golden-Plover, and Dickcissel) are of
concern only at the Region 6 and National scales,
one species (Short-eared Owl) is of concern only
within BCR 11 and Region 6, and one species
(Hudsonian Godwit) is of concern within BCR 11
and nationally, but not at a regional scale (Appendix
B). The remaining species (n= 21) are of concern at
only one scale (National = 15, USFWS Region 6 =
2, BCR = 4).
North American Waterfowl Management Plan.
The national goals set forth in the 1998 update of
the North American Waterfowl Management Plan
(NAWMP) include: (1) maintaining the current
diversity of duck species throughout North America
and achieving a continental breeding population
of 62 million ducks (mid-continent population of 39
million) during years with average environmental
conditions, which would support a fall flight of 100
million, (2) reaching or exceeding mid-continent
populations for 10 individual species, including
Gadwall, American Wigeon, Mallard, Blue-winged
and Cinnamon teal, Northern Shoveler, Northern
Pintail, Green-winged Teal, Canvasback, Redhead,
Greater and Lesser scaup, and (3) attaining an
American Black Duck mid-winter population
index of 385,000. The target populations for those
species occurring on lands comprising the Long
Lake NWR Complex are presented in Appendix B.
The plan also establishes objectives for six goose
species, three Trumpeter Swan populations, and
two Tundra Swan populations. Of these, relevant
objectives include reducing all five populations of
Canada Geese that migrate through the central
flyway and reducing mid-continent populations of
Snow and Greater White-fronted geese to 1,000,000
and 600,000, respectively. The plan also sets forth
objectives to increase the interior population of
Trumpeter Swans to 2500 and slightly reduce the
eastern population of Tundra Swans to 80,000
(Appendix B). Finally, habitat objectives for the
entire United States include protection of 2,856,785
ha, restoration of 1,249,352 ha, and enhancement of
2,922,126 ha (NAWMP, URL http://northamerican.
fws.gov/NAWMP/images/update98.PDF).
Partners In Flight North American Landbird
Conservation Plan. The North American Landbird
Conservation Plan (NALCP) is a synthesis of
priorities to guide national and international
conservation actions of 448 native landbirds from
45 families that breed in the United States and
Canada (Rich et al. 2004). Each species is assigned
a score ranging from one (low vulnerability) to five
(high vulnerability) for six factors (population size,
breeding distribution, nonbreeding distribution,
threats to breeding, threats to nonbreeding, and
population trend) (Rich et al. 2004). In addition, a
Stewardship List was developed based on avifaunal
biomes in North America. These biomes were
delineated using cluster analyses to identify groups
of BCRs that share similar avifaunas. For each
biome, Stewardship Species are those species that
have a proportionately high percentage of their
world population within a single region during
either the breeding or wintering season. The lands
comprising the Long Lake NWR Complex are in the
Prairie Avifaunal Biome, which is composed of BCRs
11, 17 - 19, and 21 - 23. Almost 40% of the species on
the Partners in Flight Watch List due to declining
population trends or high threats occur in this biome
(Rich et al. 2004, URL http://www.partnersinflight.
org, URL http://www.rmbo.org/pif/pifdb.html).
The Watch List and Stewardship List of
continentally important species in the United States
and Canada currently include 100 and 158 species
(66 species on the Stewardship List also occur on the
Watch List), respectively (Rich et al. 2004). Within
the Prairie Avifaunal Biome, there are 21 and seven
species of continental importance on the Watch
List and Stewardship List, respectively. Of these 28
species, 22 (Watch List = 16 species, Stewardship
List = six species) have been recorded as occurring
on the Long Lake NWR Complex (Appendix B).
The recommended conservation action for three of
these species is immediate action (Greater Prairie-
Chicken, Baird’s and Henslow’s sparrows), whereas
11 species (Swainson’s Hawk, Short-eared Owl, Red-headed
Woodpecker, Willow Flycatcher, Sprague’s
Pipit, Lark Bunting, Grasshopper and Harris’s
sparrows, Chestnut-collared Longspur, Dickcissel,
and Rusty Blackbird) require management and six
species (Sharp-tailed Grouse, American Tree and
Nelson’s Sharp-tailed sparrows, and McCown’s,
Lapland, and Smith’s longspurs) necessitate long-term
planning and responsibility.
14 A Preliminary Biological Assessment of Long Lake National Wildlife Refuge Complex, North Dakota
Shorebird Conservation Plan. The lands of the
Long Lake NWR Complex are in the Northern
Plains/Prairie Pothole Region (NP/PPR), an area
that encompasses more than 810,666 km2 and
includes all or portions of seven states and two
BCRs (Prairie Potholes, Badland and Prairies)
(Skagen and Thompson 2003). The landscape is
characterized by rolling prairie interspersed with
millions of depressional wetlands, intermittent and
permanent streams and rivers, and agriculture.
Thirty-six shorebird species occur in the NP/PPR,
35 of which have been observed on or adjacent to
Long Lake NWR. Of the 13 species known to breed
in the region, nine species (Piping Plover, Killdeer,
American Avocet, Willet, Spotted and Upland
sandpipers, Marbled Godwit, Wilson’s Snipe, and
Wilson’s Phalarope) have been documented as
nesting on Long Lake NWR and five of these species
(Piping Plover, American Avocet, Upland Sandpiper,
Marbled Godwit, and Wilson’s Phalarope) are listed
as species of regional concern (Appendix B). The
Piping Plover also is listed as threatened under
the Endangered Species Act. The NP/PPR also is
a major migration route for western hemispheric
shorebirds. In addition, the NP/PPR is considered
particularly important for 10 migrant shorebirds
(American Golden-Plover, Semipalmated Plover,
Lesser Yellowlegs, Semipalmated, White-rumped,
Baird’s, and Pectoral sandpipers, Dunlin, Stilt
Sandpiper, and Long-billed Dowitcher). Although
none of these species is considered a regional species
of concern, the provision of adequate stopover
habitat is a regional priority. Nearly 27% of small
shorebirds (total body length < 190 mm in the mid-continent
region migrate through the NP/PPR in
spring, whereas > 22% of medium-sized shorebirds
utilize the NP/PPR during fall migration (Appendix
B; Skagen and Thompson 2003; U.S. Shorebird
Conservation Plan, URL http://shorebirdplan.fws.
gov/RegionalShorebird/downloads/NORPLPP2.
doc).
Waterbird Conservation Region. The lands of
the Long Lake NWR Complex are located in the
Northern Prairie and Parkland Region (NPPR) of
the North American Waterbird Conservation Plan
(NAWCP). The boundaries of the NPPR occur in
two disjunctive areas that include four Canadian
provinces and five states in the U.S. The NPPR
boundary is similar to the BCR 11 boundary, but also
includes portions of BCRs 6 and 10. The NPPR also
overlaps areas covered by the Prairie Habitat Joint
Venture in Canada and the Prairie Pothole Joint
Venture (PPJV) in the U.S.
The NAWCP focuses on members of eight
orders and 22 families of birds, including coastal
waterbirds, wading birds, and marshbirds
(Waterbird Conservation for the Americas, URL
http://www.waterbirdconservation.org/waterbirds/).
There are 71 species of waterbirds that occur in
the NPPR; 24 colonial and 15 non-colonial species
that breed, and an additional 32 species that occur
as migrants or winter visitors. Of these 71 species,
59 species (33 breeding, 7 regular migrants, and 19
casual species) occur in North Dakota. Twenty of
the 33 breeding species and one (Whooping Crane)
of seven regular migrant species that occur in
North Dakota have been documented on the Long
Lake NWR (Appendix B). The conservation status
of the 20 breeding species at Long Lake NWR
includes six that are of high concern (Horned and
Western grebes, American Bittern, Yellow Rail,
Franklin’s Gull, and Black Tern), four of moderate
concern (Eared Grebe, Black-crowned Night-Heron,
Virginia Rail, and Common Tern) and 10 species
considered low risk (Beyersbergen et al. 2004, URL
http://birds.fws.gov/waterbirds/NPP/). Although
not documented as current breeders, Long Lake
NWR has documented the occurrence of two species
(Whooping Crane and Least Tern) that are listed for
protection under the Endangered Species Act.
Prairie Pothole Joint Venture. The lands
comprising the Long Lake NWR Complex are
within the boundaries of the PPJV of the NAWMP.
Joint ventures were originally conceived by the
USFWS in 1986 to implement the NAWMP.
Established in 1989, the goal of the PPJV is to
increase waterfowl populations through habitat
conservation projects that improve natural diversity
(diversity defined as an appropriate mix of plant
and animal communities that can be sustained in
association with profitable agriculture). However,
in addition to waterfowl, many joint ventures
(including the PPJV) are now incorporating an “all
bird” approach. There are 225 species that breed in
the PPR, including several grassland species (e.g.,
Lark Bunting, Grasshopper and Baird’s sparrows,
Dickcissel, and Bobolink) that have declined
significantly over the past three decades (U.S.
Prairie Pothole Joint Venture 1995). The objectives
established for the PPJV include (1) conserve
habitat capable of supporting 6.8 million breeding
ducks by the year 2001 and (2) stabilize or increase
populations of declining wetland and grassland-associated
wildlife species in the PPR, with special
emphasis on non-waterfowl migratory birds (U.S.
Prairie Pothole Joint Venture 1995). Habitat
objectives in the PPR include protection of 765,486
ha, restoration of 301,456 ha, and enhancement of
1,485,026 ha (URL http://northamerican.fws.gov/
NAWMP/images/update98.PDF).
15
Approach
The USFWS is involved in the management of more
than 607,000 ha in North Dakota (Byersbergen et al.
2004). However, many of these areas are small and
embedded within a larger landscape that has been
greatly modified by past land uses and management.
In North Dakota, agriculture represents the
primary land use, and one consequence of this
modification has been the fragmentation of the
prairie landscape into smaller parcels that has
negatively impacted many regional and local faunal
communities (Samson 1980, Johnson and Temple
1986, Knopf and Samson 1995). For example, 55
species from the Great Plains currently are listed
as threatened or endangered, and an additional
728 species represent potential additions to this list
(Flores 1995). In addition to biodiversity, however,
other important natural resource challenges also
are emerging. Past and current land uses have
negatively impacted air and water quality, water
availability, floodwater storage, and a host of other
ecosystem services (Huntzinger 1995, Krupa and
Legge 1995). Although often portrayed as separate
entities, these values are interrelated and all are
determined by ecosystem processes. For example,
the planting of non-native vegetation to reduce soil
erosion and improve water quality also directly
influences habitat suitability for different fauna.
Therefore, prior to implementing management
actions, a comprehensive evaluation of potential
changes to current ecosystem processes must be
undertaken to fully understand the implications of
different strategies. This is particularly important
today because an increasingly diverse group of
stakeholders with different attitudes and desires
are participating in natural resource management
decision making. This does not imply that all
ecosystem services must be provided on a single
NWR; rather, it suggests pertinent information on
all aspects of ecosystem services be evaluated to
maximize the probability that stakeholders with
different backgrounds and interests understand
the full range of potential trade-offs. For example, a
primary purpose of the Long Lake NWR Complex
is the provision of habitat for migratory birds and
other wildlife. However, the NWRSIA (and internal
USFWS guidance documents and policies) also
stresses the importance of biotic integrity and
ecosystem health. Thus, the impact of planned
management actions on these components, as
well as those valued by other agencies and private
landowners, should be considered.
Understanding processes should be a key factor
in natural resource management decisions. This
can only be accomplished by also considering the
formation and historical context of landscapes
(Jensen et al. 1996, Swanson et al. 1988) because
the success of management actions is constrained
by the properties of the land being managed. This
is particularly true in the Great Plains because
the environment is easy to alter, yet can collapse
quickly (Flores 1995). The authors have termed
this perspective the concept of “ecological fit” and
defined it as follows: the idea that the health and
sustainability of ecosystems depends on how well
management acts are coordinated with acts of
nature. The principal tenets of this concept are (1)
ecosystem function depends on synergistic processes
involving both uplands and wetlands, (2) a given
land unit (e.g., wetland basin) can undergo dramatic
changes in structure and function in relation
to short- and long-term acts of nature, and (3)
processes are interrelated; thus, any action intended
to alter a specific function may have unintended
results.
The following evaluation is based on the tenets of
ecological fit. However, Slade and Florence Lake
NWRs were not investigated in detail during the site
visit and little relevant information can be provided
regarding the current condition of system function
and structure. Thus, information gleaned from the
few sites visited on Slade and Florence Lake NWRs
is used throughout the remainder of this document
to draw comparisons with Long Lake NWR.
A review of records for each NWR revealed that
much information pertaining to the results of past
management actions has been recorded, but details
regarding impacts to abiotic factors (e.g., soils,
water quality) often are lacking or incomplete.
Thus, it is not possible to arrive at definitive
conclusions regarding how past management actions
have altered the systems encompassing each of
the NWRs. This is not surprising given that the
importance of these factors to management is only
beginning to be understood and applied. Therefore,
general information contained in the literature, in
combination with information provided Complex
staff, is used to identify potential challenges that
the planning team should consider when developing
the CCP. The intent is not to advocate an attempt
to return the land to pre-European settlement
conditions. This is unrealistic given the many
perturbations to the system. Rather, the intent
is to transfer information necessary to develop
Biological Assessment
16 A Preliminary Biological Assessment of Long Lake National Wildlife Refuge Complex, North Dakota
an understanding of current system function for
the purpose of assisting the Complex staff in the
development of a management program that will
achieve the goals of the Long Lake NWR Complex,
adjacent landowners, and society for productive and
sustainable natural resource benefits.
Current Conditions
Hydrology. Historically, Long Lake was part of the
ancestral Cannonball River. Fine materials (clays
and silts) transported by glacial meltwater settled in
areas of diminished flow velocities resulting in areas
with relatively impervious soils that stored large
quantities of water. In many cases (e.g., Long Lake),
these areas were sited in topographically low areas
and functioned to capture some water transported
through the valley. Following glacial retreat and
subsequent warming, obstructions (e.g., ice dams)
blocking valleys disappeared and water in the fluvial
system encompassing Long Lake was transported
through a network of channels to the Missouri River.
However, topographically low areas such as Long
Lake remained and accumulated water periodically.
The primary hydrologic input was surface water
(e.g., precipitation, runoff), but ground water
movement through adjacent terraces also influenced
lake hydrology and chemistry. Although speculative,
during years of low total inflow, surface water likely
was not discharged from these sites and was lost
only by evaporation and transpiration. In years of
high inflows, however, surface waters increased
above a natural sill and water was discharged
downstream. The variable surface water inputs that
occurred seasonally and annually, in combination
with topography (elevation ranges from 521.2 to
523.0 m above mean sea level [msl]) and ground-water
chemistry, resulted in Long Lake being
a relatively shallow, alkaline lake that exhibited
dynamic water-level fluctuations.
Although the valley encompassing Long Lake NWR
retains many historic features, the area has been
modified by both on-going natural processes and
anthropogenic forces. Perhaps the greatest change
that has impacted Long Lake NWR is hydrologic
alteration. Surface water, which enters Long Lake
via Long Lake Creek (~68%) and runoff from
surrounding uplands (~32%), remains the primary
hydrologic input to Long Lake and water is still
discharged from Long Lake to the Missouri River
via Apple Creek when surface water exceeds a
certain threshold. However, dike construction and
altered land-use patterns in the watershed likely
have altered the quantity, timing, and frequency
of water inflows and outflows. Limited information
documenting hydrologic alterations was located
for the watershed; thus, only information for
Long Lake NWR improvements obtained from
staff is provided. Following purchase in the 1930s,
the USFWS estimated that the natural outlet of
Long Lake was 522.2 m above msl. During 1936
and 1937, the Civilian Conservation Corps (CCC)
constructed three dikes (denoted as A, B, and C)
across Long Lake to form three units and built
several small dams to trap water in coulees entering
Long Lake. Several modifications to the lake dikes
(e.g., increased height and addition of water control
structures and spillways) were made during the
1940s, but two of the dikes (B and C) washed out
in 1950. In 1954, all three dikes were rebuilt to an
elevation of 524.3 m above msl and equipped with
spillways. The spillway in A Dike located at the
west end of Unit 1 was constructed at an elevation
of 523.0 m above msl, whereas the spillways in B
Dike (separating Unit 1 and Unit 2) and C Dike
(separating Unit 2 and Unit 3) were constructed at
an elevation of 523.2 m above msl (GAK). Since 1950,
additional dikes have been constructed adjacent
to Long Lake to capture surface water that enters
from natural drainage paths originating in the
uplands. In many cases (e.g., Unit 2 Marsh), these
impoundments can be flooded either by natural
runoff or by transporting water from Long Lake
via gravity flow, but dewatering is dependent on
evapotranspiration. Currently, the staff can manage
water in seven impoundments (three units of Long
Lake and four impoundments) on Long Lake NWR.
The specific hydrologic impacts of dike construction
are difficult to determine due to limited on-site
information. However, the construction of dikes
across the lake obstructed water movement within
the original lake bed. Lake bathymetry data were
not located, but observation suggests the dikes
were constructed across the natural elevation
gradient. Thus, the pattern and timing of flooding in
different portions of Long Lake was altered because
water from Long Lake Creek was sequentially
impounded behind each dike until a sufficient volume
accumulated to discharge water over the spillway
into the next unit. In contrast, the historic flooding
pattern was determined by natural elevation
gradients throughout the entire lake basin (e.g.,
water entering Long Lake pooled first in lowest
areas throughout the basin). Second, spillways were
constructed to heights greater than two feet above
the elevation of the historic lake outlet. Therefore,
the potential depth of flooding was increased.
Available inflow records indicate Long Lake
Creek is a perennial stream that exhibits sporadic
flows. Thus, although the creek represents a
reliable source of water, the volume of water is not
predictable. For example, no water was discharged
over the spillway in A Dike in 13 of 25 years between
1963 and 1987 (GAK). During this period, inflows
from Long Lake Creek ranged from 895 to 5836 ha-m
(average = 2253 ha-m). In contrast, during years
when water was discharged over A Dike, inflows
ranged from 1862 to 12,506 ha-m (average = 6235
ha-m). Coupled with the requirement to flood units
sequentially, these data, although imprecise, suggest
land comprising Unit 1 is flooded more frequently
and to a greater extent than would occur naturally,
whereas some land comprising Unit 3 is flooded less
frequently and for shorter time periods compared
to historic conditions. For example, Unit 3 was dry
by mid-August in six of the 13 years that no water
was discharged over the spillway in A Dike. During
this period, the surface flooding recorded in Unit
17
3 likely resulted from discharge of surface water
from several large coulees that drain surrounding
uplands and discharge directly into Units 2 and
3. The amount of water entering each unit is not
known, but staff estimated that Long Lake Creek
represented only 68% of the surface water input. If
correct, the remaining 32% of runoff originates from
other sources such as coulees that drain surrounding
uplands and discharge directly into each unit. In
some years, this input could be substantial. For
example, during the period 1963 to 1986, annual
precipitation recorded at Long Lake NWR ranged
from 23.6 to 55.9 cm and averaged 40.8 cm during
years when water was not discharged over the
spillway in A Dike. However, this information does
not adequately represent current inputs because
additional dikes have been constructed across some
of these coulees since 1986 (e.g., Unit 2 Marsh
completed in 1987). Thus, the amount of surface
inflows to Long Lake via these drainage paths has
likely been reduced.
In general, all dikes on Long Lake NWR were
installed to improve water management flexibility.
However, a primary purpose for separating Long
Lake into units was to better manage water to
prevent botulism outbreaks (USFWS 1988). Thus,
many of the aforementioned hydrologic alterations
caused by dikes were intentional. For example, the
goal of water management from 1944 to 1959 was to
fill Unit 1 to 523.0 m, Unit 2 to 522.9 m, and Unit 3
to 522.7 m above msl. This strategy was considered
highly effective for Units 1 and 2, but Unit 3 could
not reliably be stabilized and frequently went dry.
Between 1960 and 1987, the water management
strategy basically remained the same for Units 1 and
2, but Unit 3 was maintained in as dry a condition as
possible. Although Unit 3 was dry nine of these 28
years, records indicate that the water management
capability was inadequate to reliably meet these
goals (USFWS 1988), which indicates that natural
climate cycles still influenced water-level fluctuations
to some extent. The current strategy is based on
water elevations in the spring; if water levels do not
exceed a certain threshold (522.9 m msl), Unit 3 is
kept as dry as possible; otherwise Unit 3 is flooded
to the extent possible.
The success of these water management strategies
in reducing botulism outbreaks is difficult to
interpret. Prior to initiating water management in
1944, the estimated total avian deaths from botulism
between 1937 and 1943 exceeded 375,000 and
ranged from 75 in 1938 to 145,000 in 1941 (Figure
2). In contrast, the total estimated loss between
1944 and 2004 was only 82,953 birds (range = 0 to
18,700) (McEnroe 1986, USFWS 1988, USFWS
unpublished data). This suggests that developing
the ability to control water levels provided some
ability to ameliorate the incidence and extent of
botulism outbreaks. However, numerous factors
are involved in the progression from the initiation
and propagation phases to large botulism outbreaks
(Wobeser 1997). Further, there are likely many
alternative pathways that lead to an outbreak;
thus, determining effective management practices
is hampered by an incomplete knowledge of the
environmental factors that precipitate outbreaks
(Wobeser and Bollinger 2002). In general, it has been
recommended that control efforts need to focus on
three important factors: (1) fluctuating water levels
during hot summer months, (2) an abundance of
flies, and (3) presence of animal carcasses necessary
for toxin production (Lock and Friend 1989). Thus,
although it is plausible that water management
contributed to prevention, other factors likely were
involved as well. For example, factors reported as
potentially signifying an increased risk of a botulism
outbreak include increasing temperature, increasing
invertebrate abundance or biomass, and decreasing
turbidity (Rocke et al. 1999). Unfortunately, data
on botulism deaths and environmental factors
for each individual unit were not located; thus,
any conclusions regarding the effects of water
management would be extremely speculative.
Sediment and Nutrient Dynamics. Regardless of
how effective water management strategies have
been with respect to controlling the incidence and
extent of botulism outbreaks, human perturbations
have likely impacted other processes that determine
system structure and function, including the
interrelated factors of sediment dynamics and
nutrient loads. These factors are important
because they affect both upland and wetland plant
community dynamics. Inorganic nutrients provide
the chemical constituents that form the basis of
the entire food chain. Common nutrients needed in
large quantities for cell development include oxygen,
carbon, phosphorous, silica, sulfur, iron, magnesium,
calcium, potassium, nitrogen, and hydrogen,
whereas manganese, molybdenum, copper, zinc, and
cobalt are minor nutrients that may occasionally be
in short supply (Salisbury and Ross 1978, Goldman
and Horne 1983, Table 11). Ionic compounds (e.g.,
sodium, potassium, and chloride) affect ion exchange
at the surface of cell membranes, whereas toxic
compounds can negatively impact nutrient cycling
by causing mortality of plants or animals. Some
inorganic compounds (e.g., copper and zinc) can
act either as toxicants or as growth stimulators. In
contrast, organic compounds tend to occur in small
quantities in natural systems and some (e.g., humic
acids and citrate) can alter the chemical state of
water by changing the ionic state of metals that
might otherwise be toxic.
The primary factors determining daily, seasonal,
and long-term cycles of major elements in natural
systems are rainfall, evaporation, erosion and
solution, sedimentation, and biological components
of the watershed (Goldman and Horne 1983).
These factors, in turn, are influenced by parent
material, climate, topography, and vegetation
cover in the watershed. The extent that human
perturbations have altered sediment dynamics and
nutrient loads on each NWR cannot be determined
directly because records are lacking or sporadic.
However, soil organic matter greatly influences
productivity by functioning as a binding agent
18 A Preliminary Biological Assessment of Long Lake National Wildlife Refuge Complex, North Dakota
that aids soil structure formation and stability,
which is critical to maintaining adequate water
infiltration and potential water storage (Peterson
and Cole 1995). In addition, organic matter also is
a primary requisite for retaining certain nutrients,
particularly nitrogen. Therefore, loss of surface
horizons in terrestrial habitats reduces nitrogen
availability and, if sufficient losses occur, results
in reduced plant productivity (Peterson and Cole
1995). Thus, concerns associated with past and
current agricultural practices are not limited only
to the fragmentation and loss of native vegetation
that reduces habitat suitability for native wildlife.
Rather, these activities also can accelerate soil
erosion that can reduce the potential productivity of
sites suffering soil loss, as well as negatively impact
sites receiving increased sediment overburden
(Kothmann 1995).
The extent that soil erosion and nutrient
redistribution has occurred on lands encompassed
by all three NWRs is unknown. However, 87% of
improved prairie farmlands in the Great Plains are
characterized as exhibiting medium to high erosion
risk (Sopuck 1995) and the estimated average
annual sheet and rill erosion on non-federal rural
land for North Dakota in 1987 was 0.8 tons per ha
in cropland, 0.2 tons per ha in pastureland, and 0.4
tons per ha in rangeland, whereas the estimated
average annual wind erosion on cultivated and
non-cultivated cropland was 1.7 tons per ha and
0.08 tons per ha, respectively (Kothmann 1995).
Thus, it is likely that some soil erosion has occurred,
particularly in areas with steeper slopes that have
a history of cropping. In contrast, erosion is of
less concern in areas of lesser impact. We provide
two examples to illustrate this point. The first is
from soil cores collected at Florence Lake NWR in
an area that has been minimally impacted by past
land uses. A core collected in a seasonal wetland
suggested the presence of a deep A horizon on the
surface and an argillic B horizon at about 16 in (40.6
cm). Further, soils were not mixed and exhibited
a structure characteristic of a relatively unaltered
wetland substrate. A second core collected at the top
of a hill adjacent to this wetland also exhibited a well
developed A horizon to a depth of 12.7 to 15.2 cm and
an underlying B horizon, suggesting minimal soil
erosion has occurred.
The other example is from soil cores collected in
Unit G7 and Unit 2 Marsh of Long Lake NWR.
Based on the county soil survey, soils in Unit G7
exhibit a sand mantle and a past land use history
that may have included farming. The soil core
collected near a knoll in this unit indicated that
soil structure was generally lacking. The top 10 cm
contained little organic material and was assumed
to represent the A horizon and the underlying B
horizon (10 - 20 cm) contained a mix of sand with
small amounts of clay. The second core collected
at the toe-slope of the same hill also indicated
minimal soil structure, but the A horizon was at
least 20 cm in depth and contained substantially
more organic matter. Although not definitive, these
two cores suggest that soil from the slopes has been
transported (i.e., eroded) to surrounding low areas.
In conventional agriculture, the solution to soil
degradation has consisted of using biological and
chemical inputs (e.g., fertilizers) to replace nutrient
losses (Sopuck 1995) and planting crop varieties
adapted for growth under altered conditions.
However, this complement of options often is not
available when attempting to restore native prairie
vegetation. First, the term native refers to plants
that originally occupied the site of interest; thus
planting new “varieties” is not plausible even if they
were available. Second, unlike crop monocultures,
mixed-grass prairie consists of numerous grass and
forb species that exhibit a non-random distribution
determined by abiotic factors (e.g., soil topography,
climate). Therefore, application of fertilizer will
not overcome the problems associated with the
differential loss of organic matter. Finally, frequent
cultivation to control introduced tame grasses and
invasive plants cannot be performed simultaneously
with the reestablishment of native grasses and forbs
without causing mortality of desirable species.
In contrast to terrestrial sites, primary productivity
of many disturbed wetlands often is reduced due
to the excessive accumulation of sediments and
nutrients (Rybicki and Carter 1986, Dieter 1991,
Hartleb et al. 1993, Jurik et al. 1994, Wang et al.
1994, Gleason and Euliss 1998, Gleason et al. 2003).
In terms of quantity, sediment has become the
major pollutant of wetlands, lakes, estuaries, and
reservoirs in the United States (Baker 1992) and
many river systems are now considered degraded
(Longcore et al. 1987, Grue et al. 1989). The greatest
causes of altered water chemistry are contamination
from agriculture, road construction, and industry
(Ulrich and Pfeifer 1976, Swanson et al. 1988, Euliss
et al. 1999) because these activities can alter the
distribution of soils and sediments, which can act as
both a sink and source for water quality constituents.
In some cases, productivity can be affected by an
imbalance in a single element. For example, salinity
can directly inhibit germination and growth of
plants (Swanson et al. 1988, Kantrud et al. 1989) and
excessive additions of phosphorous (e.g., fertilizer
runoff) can lead to extensive algal blooms that
inhibit growth of some submerged aquatic plants
(Robel 1961, Kullberg 1974, Swanson et al. 1988). In
other situations, however, water-borne elements can
act alone or synergistically to affect productivity. For
example, salinity can exacerbate boron toxicity in
several plant species (Wimmer et al. 2003). Further,
suppression of primary production often negatively
impacts secondary productivity. For example,
salinity can influence invertebrate composition
directly by affecting physiology (Newcombe and
MacDonald 1991, Euliss et al. 1999) or indirectly
by affecting habitat structure and foods (Krull,
1970, Wollheim and Lovvorn 1996). Other examples
include documented reports that high concentrations
of suspended silt and clay are toxic to zooplankton
(Newcombe and MacDonald 1991)
19
and agrichemicals can cause significant mortality of
aquatic invertebrates (Borthwick 1988).
As mentioned previously, natural systems exhibit
plasticity to fluctuations in water quality and
sediments. For example, natural concentrations
of dissolved solids within a single closed-basin
wetland can fluctuate from fresh to extremely saline
depending on climatic variables that influence
hydrology (Swanson et al. 1988, LaBaugh 1989).
Historically, the water chemistry of Long Lake
likely was dynamic given that it was part of a
riverine system characterized by sporadic flows that
resulted in fluctuating lake levels. Intact upland and
floodplain vegetation attenuated surface runoff and
soil erosion, and acted as a filter to limit the amount
of sediment that entered the creek channel and
surrounding coulees. During periods of extended
low flow, the volume of water entering Long Lake in
some years was insufficient to overtop the natural
outlet (elevation = 522.2 m); thus, Long Lake
represented a terminal point of water collection.
When this occurred, discharge of water downstream
of Long Lake did not occur and water loss occurred
only by evapotranspiration. This would tend to
cause an increase in the concentration of organic
and inorganic compounds. In contrast, during
years of higher flow, the volume of water entering
Long Lake would be sufficient to breach the natural
outlet and water would be discharged downstream.
During these periods, the concentration of organic
and inorganic compounds in surface waters of Long
Lake would decrease due to dilution and transport
downstream. Unfortunately, data from USGS
gauge stations above and below Long Lake are only
available for a brief period in the late 1980s and early
1990s; therefore, it is not possible to evaluate the
frequency with which these two extremes occurred.
Nonetheless, the concentration of nutrients and
elements in the waters of Long Lake likely was
dynamic because variable surface water inputs
resulted in the occasional concentration and dilution
of nutrients and other elements as the region
experienced climate extremes ranging from drought
to deluge.
However, alterations that affect fundamental
processes (e.g., hydrology, water chemistry,
sediment dynamics) often alter system tolerance
and can result in significant shifts in plant and
invertebrate communities. River systems are
concentration points for sediments and chemical
constituents bound to sediments because they
collect runoff from surrounding uplands. Thus,
sediment transport and deposition is a naturally
occurring process that affects formation, structure,
and function of wetlands (Saucier 1994). Prior to
human alteration, areas of transport and deposition
tended to change temporally in response to channel
characteristics that influenced flow velocities. Long
Lake likely represented an area of accumulation
within the watershed, but dynamic flow patterns
resulted in periods of concentration and dilution.
Further, the amount of sediment and bound
constituents entering the system was within normal
bounds and excess nutrients (e.g., nitrogen and
phosphorus) could be processed without risk to
long-term productivity. For example, wetlands
may be capable of removing 70 to 90% of nitrogen
entering a system (Gilliam 1994) and 20 to 100%
of metals, depending on wetland type, individual
site characteristics, and metal type (Taylor et al.
1990, Gambrell 1994). However, construction of
dikes within the floodplain on Long Lake has likely
contributed to altered sediment and chemical
deposition patterns by changing flow velocities
and other hydrologic parameters, including the
frequency, depth, and time of flooding. Further, the
type of alteration differs depending on the location
of one dike relative to other dikes. For example,
the upstream unit (Unit 1) likely receives a greater
volume of water annually and discharge over the
spillway occurs more frequently compared to the
dike separating Unit 2 from Unit 3. As a result,
the frequency of flushing flows likely decreases
sequentially from Unit 1 to Unit 3. Coupled with
potential increases in the amount of material
entering the system, it is possible that sediment
loads and concentrations of certain constituents vary
within each unit.
Information on the rate of sediment accretion
in wetlands was not located, but Complex staff
indicated that palustrine wetlands surrounded by
croplands likely have accrued sediment. During
the site visit, soils inspected in a seasonal wetland
on Slade NWR and in Unit 2 Marsh on Long Lake
NWR also suggested that sediment accrual has
occurred and turbid conditions in the Long Lake
units suggested the presence of some unconsolidated
sediments. In addition, a few historic records were
located that compared water chemistry on either
side of a single dike on Long Lake. In 1969, the
chemistry on the east side of an unspecified road
exhibited greater total alkalinity and specific
conductivity and increased concentrations of sulfate
chloride sodium, and potassium compared to the
water on the west side of the same road (Swanson
et al. 1988). Similar observations were recorded
during the site visit; the specific conductivity of
water in Units 1, 2, and 3 exhibited increasing values
of 1910, 2600, and 4200 μS per cm, respectively.
Although these limited data suggest changes in
sediment dynamics and water chemistry, it is not
possible to determine the extent that these observed
differences are due to natural variation in climate
(LaBaugh and Swanson 2004) as opposed to long-term
changes resulting from dike construction and
altered land use patterns.
Information also is lacking to quantify the extent
that human influences have altered dynamic
fluctuation of nutrients (e.g., nitrogen, phosphorous)
and other elements (e.g., mercury, boron, arsenic) in
the Long Lake Units. However, relative to historic
conditions, management actions have increased
water storage volumes up to three feet above the
natural sill in the three Units. Retaining more
water in the Units than would occur naturally,
in combination with altering the frequency of
20 A Preliminary Biological Assessment of Long Lake National Wildlife Refuge Complex, North Dakota
flushing flows, will increase the overall potential for
accumulation of various ions, elements, and other
dissolved solids via evaporative processes. This
potential can be demonstrated by using information
on specific conductance and estimates of average
annual lake evaporation. For example, total dissolved
matter can be estimated from specific conductance
data by multiplying by an empirical factor that
typically varies from 0.5 to 1.0 (Figure 3). Ideally,
the relationship between specific conductance
and total dissolved matter is determined for a
particular location. However, since this information
is lacking, we used the factor 0.65 suggested by
Rainwater and Thatcher (1960) because it provides
a good approximation of total dissolved matter data
presented in Table 3. Using this factor, estimates
of total dissolved matter were within 3% (range
= 1 to 6%) of those reported in Table 3. Given this
relationship, each ha-m of water with a specific
conductance of 1000 μS per cm that was stored and
evaporated would result in the accumulation of 7.33
tons of total dissolved matter. When extrapolated
to the area of each Unit (Unit 1 = 507.5 ha, Unit 2 =
827.6 ha, and Unit 3 = 5369.2 ha), the evaporation
of 30.5 cm of water from all Units combined would
result in the accumulation of 14,987.8 tons of
dissolved matter (e.g., 6704 ha * 7.33 tons * 0.305).
However, the amount of dissolve matter actually
accumulated in each Unit will vary depending on
evaporation rates (Figure 4). Given that the average
annual lake evaporation for this region can exceed 91
cm (Shjeflo 1968), the above estimate is considered
conservative.
Based o